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COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


PRUNING  IN  CALIFORNIA 


By  FREDERIC  T.  BIOLETTI 


The  native  vine  of  California  (Vitis  California). 


REVISION  OP 

BULLETINS  Nos.  241  and  246 

JUNE,  1921 


UNIVERSITY  OF  CALIFORNIA  PRESS 

BERKELEY 

1921 


DAVID  P.  BARROWS,  President  of  the  University. 


EXPERIMENT  STATION  STAFF 

HEADS  OF  DIVISIONS 

THOMAS  FORSYTH  HUNT,  Dean. 
EDWARD  J.  WICKSON,  Horticulture  (Emeritus). 
WALTER  MULFORD,  Forestry,  Director  of  Resident  Instruction. 
CLARENCE  M.  HARINQ,  Veterinary  Science,  Director  Agricultural  Experiment 
Station. 

B.  H.  CROCHERON,  Director  of  Agricultural  Extension. 
HUBERT  E.  VAN  NORMAN,  Vice-Director,  Dairy  Management. 

JAMES    T.    BARRETT,   Acting   Director    of    Citrus    Experiment   Station,   Plant 

Pathology. 

WILLIAM  A.  SETCHELL,  Botany. 
MYER  E.  JAFFA,  Nutrition. 
RALPH  E.  SMITH,  Plant  Pathology. 
JOHN  W.  GILMORE,  Agronomy. 
CHARLES  F.  SHAW,  Soil  Technology. 
JOHN  W.  GREGG,  Landscape  Gardening  and  Floriculture. 
FREDERIC  T.  BIOLETTI,  Viticulture  and  Fruit  Products. 
WARREN  T.  CLARKE,  Agricultural  Extension. 
JOHN  S.  BURD,  Agricultural  Chemistry. 
CHARLES  B.  LIPMAN,  Soil  Chemistry  and  Bacteriology. 
ERNEST  B.  BABCOCK,  Genetics. 
GORDON  H.  TRUE,  Animal  Husbandry. 
FRITZ  W.  WOLL,  Animal  Nutrition. 
W.  P.  KELLEY,  Agricultural  Chemistry. 
H.  J.  QUAYLE,  Entomology. 
ELWOOD  MEAD,  Rural  Institutions. 
H.  S.  REED,  Plant  Physiology. 
J.  C.  WHITTEN,  Pomology. 
•FRANK  ADAMS,  Irrigation  Investigations. 

C.  L.  ROADHOUSE,  Dairy  Industry. 
R.  L.  ADAMS,  Farm  Management. 

F.  L.  GRIFFIN,  Agricultural  Education. 
JOHN  E.  DOUGHERTY,  Poultry  Husbandry. 
W.  B.  HERMS,  Entomology  and  Parasitology. 
L.  J.  FLETCHER,  Agricultural  Engineering. 
EDWIN  C.  VOORHIES,  Assistant  to  the  Dean. 


F.  T.  BIOLETTI  L.  O.  BONNET 

W.  V.  CRUESS  G.  BAROVETTO 

A.  W.  CHRISTIE 


*  In  cooperation  with  office  of  Public  Roads  and  Rural  Engineering,  U.  S.  Department  of 
Agriculture. 


CONTENTS 


A.  INTRODUCTION 

PAGE 

Literature:  Need  of  the  Bulletin  5 

Definition:  Objects;  Scope 5-6 

Some  Results  of  Defective  Pruning 6 

B.  HABITS  AND  CHARACTERISTICS  OP  THE  VINE 

Vitis  Vinifera:  Structure  of  a  Cultivated  Vine 9 

Pruning  and  Descriptive  Terms  11 

Roots;   Trunk;   Head;   Branches;   Arms;   Spurs;   Fruit   Canes;   Buds; 

Shoots;  Water-sprouts;  Suckers;  Laterals;  Fruit  Wood;  Sterile  Wood. 

C.  THE  PRINCIPLES  OF  PRUNING 

Physiological  Principles  25 

Winter  Pruning  _ 26 

Season;  Amount;  Young  and  Old  Vines;  Units  of  Pruning. 

Summer  Pruning  34 

Weakening  effect;  Concentrating  effect;  Uses;  Disbudding;  Thinning 
of  Shoots;  Topping  Young  Vines;  Suckering;  Water-sprouting;  Pinch- 
ing; Topping;  Defoliating;  Thinning  the  Fruit;  Ringing;  Cutting 
Surface  Roots. 

Restriction  and  Treatment  of  Wounds  44 

Supports:  Staking,  Trellising  47-50 

Pruning  Tools:  Disposal  of  Prunings  51 

Principles  of  Economy  53 

D.  THE  PRACTICE  OF  PRUNING 

Pruning  Systems:  Ideals  of  Pruning;  Calif ornian  Systems 55 

Periods  of  Development:  Before  Planting;  Planting  64-68 

First  Season:  First  Winter  Pruning;  Staking  « 69-71 

Second  Season:  Summer  Pruning;  Second  Winter  Pruning  72-74 

Third  Season:  Summer  Pruning;  Third  Winter  Pruning  79-80 

Pruning  after  the  Third  Winter 84 

Fan-shaped  Vines  and  Long  Pruning;  Double-headed  Vines 89-91 

Vertical  Fruit  Canes;  Bowed  Fruit  Canes  93 

Vertical  Cordons:  Single;  Double;  Multiple 95 

Horizontal  Cordons:  Unilateral;  Bilateral 97 

Renovation  of  Imperfect  and  Misshapen  Vines 103 

Choice  of  System:  List  of  Varieties  for  Long,  Half-long,  and  Short  Pruning  106 


ILLUSTRATIONS 


Fig.   41 


Cover  Cut,  Wild  Vine  of  California    (Viti*  Fig.   39. 

Calif  ornica) . 

Fig.     1.  Trunks  of  V.  Californica.  Fig.  40. 

Fig.     2.  Root  crown   of  four-year-old  vine. 

Fig.  3.  Typical  cultivated  vine  with  short 
arms. 

Fig.     4.  Typical   cultivated   vine   with   long 

arms. 

Fig.     5.  Vine  "eye,"  cross  section. 
Fig.     6.  Fruit  bud,   cross  section. 
Fig.      7.  Fruit  bud,   longitudinal   section. 
Fig.     8.   Sterile    bud,    longitudinal    section. 
Fig.     9.   Shoot  showing  position  of  blossom 

bunches. 

Fig.   10.   Shoot  showing  laterals  and  second 

crop.  Fig.  49. 

Fig.   11.  Unit  of  short  pruning. 

Fig.   12.  Unit  of  long  pruning. 

Fig.  13.  Tokay  bunch  before  and  after  thin- 
ning. 

Fig.  14.  Black  Morocco  bunch  improved  by 
thinning. 

Fig.   15.   "Cincturing"  knife  for  ringing. 

Fig.  16.  Fungous  decay  due  to  large  prun- 
ing wounds. 

Fig.   17.  Position  of  pruning  shears. 

Fig.  18.  Method  of  cutting  the  end  of  a 
spur. 

Fig.   19.  Pruning  tools. 

Fig.  20.  Burning  the  "brush"  after  prun- 
ing. 

Fig.  21.   Brush  burner. 

Fig.  22.  Forms  of  head  pruning,  spurs  and 
half-long. 

Fig.   23.  Forms  of  head  pruning,  long  fruit 

canes. 
Fig.   24.  Trellised  vine  with  fan-shaped  head 

and  long  fruit  canes. 
Fig.  25.   Single  vertical  cordon. 
Fig.   26.  Unilateral  horizontal  cordon. 
Fig.  27.  Forms  of  cutting. 
Fig.  28.   Bundle  of  one-year  rooted  vines. 
Fig.  29.  Rooted  vine  with  single  cane. 
Fig.   30.  Rooted  vine  with  two  canes.  Fig.   66. 

Fig.  31.  Rooted    vine    with    canes    at    two  Fig.   67. 

levels. 

Fig.   32.  Rooted     vine     pruned     ready     for  Fig.   68. 

planting. 
Fig.   33.  Ro-trd  vine  with  roots  at  different  Fig.   69. 

levels. 

Fig.  34.  Result  of  planting  too  deep.  Fig.   70. 

Fig.  35.  Root  growth  of  a  properly  pruned 

and  properly  planted  young  vine.  Fig.   71. 

Fig.  36.  Growth    of    vine    during    the    first 

summer.  Fig.   72, 

Fig.  37.  Vine  at  end  of  first  growing  season. 
Fig.  38.  Growth  and  treatment  during  the  Fi&-   73 

second  growing  season.  Fig.   74. 


Fig. 
Fig. 
Fig. 
Fig. 

Fig. 

Fig. 
Fig. 


Fig. 
Fig. 


Fig. 
Fig. 

Fig. 
Fig. 
Fig. 

Fig. 
Fig. 
Fig. 

Fig. 
Fig. 

Fig. 
Fig. 


Fig.   65, 


Second  winter  pruning  for  head 
of  medium  height. 

Second  winter  pruning  for  high 
head. 

Second  winter  pruning  of  very 
vigorous  vine. 

Third  spring,  ready  for  disbudding. 

Third  spring,  cane  too  short. 

Vineyard  during  the  third  summer. 

Crop  at  the  end  of  the  third  season. 

Three-year-old  vine  ready  for  prun- 
ing. 

Three-year-old  vine  pruned. 

Three-year-old  vines  pruned:  A,  for 
vase-formed;  B,  for  fan-shaped 
head. 

Four-year-old  vine  pruned  for  vase- 
formed  head. 

Four-year-old  vine  with  high  head. 

Seven-year-old  vine  with  fully  de- 
veloped vase-formed  head. 

Nine-year-old  vine  with  fully  de- 
veloped vase-formed  head  pruned. 

Fifteen-year-old  vineyard. 

Four-year-old  fan-shaped  vine  be- 
fore pruning. 

Four-year-old  fan-shaped  vine  after 
pruning. 

Trellised  vineyard  of  Sultanina  de- 
fective. 

Trellised  Sultanina  vine  in  full 
bearing. 

Double-headed  vine  on  trellis. 

Vine  with  vertical  canes. 

Vineyard  with  vertical  fruit  canes 
defective. 

Vertical  cordon,  young  vine  un- 
pruned. 

Vertical       cordon,       young       vine 

pruned. 

Vineyard  of  vertical  cordons. 

Vertical  cordon,  ultimate  form  un- 
pruned. 

Vertical  cordon,  ultimate  form 
pruned. 

Vertical  cordon  with  double  trunk. 

Forming  the  cordon,  second  winter 
pruning. 

Half-long  pruning  of  horizontal 
cordons. 

Horizontal  cordon,  unilateral,  short 
pruned. 

Horizontal  "cordon,  unilateral,  long 
pruned,  defective. 

Vineyard  of  horizontal  cordons,  un- 
ilateral, defective. 

Vineyard  of  horizontal  cordons,  bi- 
lateral. 

Young  vine  with  imperfect  top. 

Pruning  to  renew  imperfect  top. 


VINE   PRUNING  IN   CALIFORNIA 

BY  FREDERIC  T.  BIOLETTI 


PART  I 

INTRODUCTION 

Literature. — A  large  number  of  books  have  been  published  on  the 
pruning  of  the  vine,  but  none  of  them  are  very  well  adapted  to  the 
needs  of  the  Californian  vine  grower.  Most  publications  in  English 
refer  to  methods  suited  to  the  eastern  states  and  to  eastern  varieties 
or  to  the  conditions  of  hothouse  cultivation.  Foreign  publications, 
besides  being  more  or  less  inaccessible,  refer  to  conditions  different 
from  those  of  the  Pacific  Slope  or  treat  the  subject  so  broadly  that  the 
grower  is  at  a  loss  to  choose  from  such  a  mass  of  material. 

Need  of  the  Bulletin. — The  demand  for  information  on  vine  prun- 
ing is  large  and  the  need  for  such  information  is  made  evident  by  the 
unsightly,  defective,  and  unprofitable  condition  of  many  of  our  vine- 
yards. This  seems  a  suitable  time  for  the  publication  of  a  new  bulletin 
which  will  incorporate  the  experience  of  the  older  and  more  skillful 
grape  growers  and  the  results  of  the  experiments  and  observations  of 
the  experiment  station  workers.  The  constant  influx  of  new  settlers, 
who  are  planting  and  growing  vines  with  little  knowledge  of  the 
methods  which  have  proved  best  in  California,  and  the  opening  up  of 
new  vine-growing  districts  make  necessary  some  guide  that  will  help 
to  avoid  the  numerous  mistakes  made  in  the  past. 

Definition. — The  term  pruning,  both  by  derivation  and  usage,  is 
applied  to  various  operations  performed  in  cutting  off  certain  portions 
of  the  vine.  There  are  other  operations,  however,  the  purpose  of  which 
is  similar  or  identical,  which  must  logically  and  for  convenience  be 
discussed  at  the  same  time.  Some  of  these  are  the  removal  of  buds  and 
shoots  by  other  means  than  cutting,  and  the  attachment  of  the  vine 
or  its  parts  to  stakes,  wires,  or  other  supports.  For  this  reason  some 
writers  call  the  subject  the  "pruning  and  training  of  the  vine."  The 
word  ' '  training, ' '  however,  is  misleading  when  applied  to  any  of  the 
vineyard  operations  used  in  California.  It  implies  methods  of  shaping 
the  vine  which  we  do  not  use,  and  it  does  not  properly  describe  the 
various  operations  of  suckering,  disbudding,  water-sprouting,  and  the 
attachment  of  fruit  canes  which  we  do  use.  The  word  pruning,  more- 
over, seems  sufficient  alone,  as  all  the  other  operations  follow  and  are 
necessitated  by  the  methods  of  cutting  or  pruning-proper  adopted. 

Objects. — The  main  objects  of  pruning,  in  the  wider  sense,  are  first, 
to  give  the  vine  a  suitable  form  and  to  conserve  this  form ;  and  second, 


6  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

to  so  regulate  the  bearing  that  the  maximum  quality  and  quantity  of 
crop  may  be  obtained  for  a  long  series  of  years  at  the  minimum  expense. 

Scope. — The  crop  possibilities  of  a  vineyard,  both  as  regards  quan- 
tity and  quality,  depend  on  many  factors,  of  which  the  chief  are  the 
character  of  soil  and  climate,  the  amount  of  available  water,  and  the 
nature  of  the  variety  of  vine.  What  part  of  these  possibilities  is 
realized  depends  on  the  operations  of  the  vineyardist — on  how  he 
handles  the  soil  and  the  vine.  One  of  the  most  important  of  these 
operations  is  pruning.  By  improper  pruning  we  may  neutralize  the 
most  favorable  conditions  and  destroy  the  effect  of  the  most  careful 
cultivation.  The  skillful  pruner,  on  the  other  hand,  gives  his  vines  the 
opportunity  to  utilize  to  the  full  all  the  natural  and  cultural  advan- 
tages. Many  vineyards  produce  less  than  half  their  proper  average 
crop  owing  to  mistakes  in  pruning,  and  there  are  few  vineyards  in  the 
state  where  both  the  amount  and  the  quality  of  the  crop  could  not  be 
increased  considerably  by  improved  methods  of  pruning. 

There  are  two  great  difficulties  in  the  way  of  reforming  the  pruning 
methods  in  most  vineyards.  One  is  the  difficulty  of  obtaining  pruners 
possessed  of  the  necessary  skill  and  knowledge.  The  other  is  the  lack 
of  the  proper  knowledge  on  the  part  of  the  owner  of  the  vineyard. 
Of  these  difficulties,  the  latter  is  by  far  the  more  serious  in  its  effects 
and  its  removal  would  in  most  cases  obviate  the  greater  part  of  the 
trouble  resulting  from  the  former. 

Some  Results  of  Defective  Pruning. — In  order  to  emphasize  the 
necessity  for  proper  pruning,  it  may  be  well  to  consider  some  of  the 
results  of  defective  pruning  as  shown  below : 

1.  Deficient  average  annual  amount  of  crop  due  to: 

(a)  Delay  of  bearing  of  young  vines. 

(&)  Irregularity  of  development  of  vines. 

(c)  Failure  to  utilize  properly  full  vigor  of  best  vines. 

(d)  Lack  of  sufficient  fruit  buds. 

2.  Inferior  quality  due  to : 

(a)  Overbearing  of  weak  vines. 

(&)   Irregular  distribution  of  the  grapes  and  consequent  irreg- 
ular ripening, 
(c)   Injurious  contact  of  grapes  with  soil,  canes,  and  each  other. 

3.  High  cost  of  vineyard  operations,  such  as: 

(a)  Cultivation,  plowing,  hoeing. 

(&)  Pruning,  suckering. 

(c)  Control  of  diseases,  oidium,  vine-hopper. 

(d)  Gathering,  trimming,  sorting,  culling. 


BULLETIN  241-246  VINE  PRUNING   IN   CALIFORNIA  7 

4.  Shorter  life  of  vines  due  to: 

(a)  Pruning  and  cultivation  wounds. 
(6)   Occasional  overbearing. 
(c)   Growth  of  suckers. 

A  young  vine  under  average  conditions  in  California  should  bear 
a  paying  crop  at  three  years;  that  is,  in  the  autumn  of  the  third  leaf 
or  third  summer  in  the  field.  At  four  years  it  should  be  practically 
in  full  bearing.  Under  exceptionally  favorable  conditions,  bearing 
may  be  nearly  a  year  earlier  than  this.  In  the  cooler  regions  and  with 
certain  varieties,  a  year  longer  may  be  necessary.  These  results  can 
be  obtained  only  when  the  pruning  during  the  first  years  is  properly 
done. 

Irregularity  of  development  of  individual  vines  is  incompatible 
with  the  highest  returns  for  the  whole  vineyard.  Vines  dwarfed  by 
defective  pruning  can  not  compete  with  their  more  vigorous  neighbors 
and  will  fail  to  produce  a  full  crop.  Full  returns  from  a  vineyard 
can  be  obtained  only  when  there  is  comparative  uniformity  of  vigor 
in  the  individual  vines.  This  uniformity  can  be  secured  only  by  care- 
fully adapting  the  pruning  to  each  case.  If  vigorous  and  weak  young 
vines  are  pruned  alike,  the  former  may  bear  nothing  and  increase  their 
vigor  while  the  latter  may  bear  worthless  grapes  and  increase  their 
weakness. 

When  the  vines  reach  the  age  of  full  bearing,  the  failure  to  adapt 
the  pruning  to  the  individual  case  is  equally  disastrous.  A  method 
of  pruning  adapted  to  a  weak  vine  would  prevent  a  vigorous  vine  from 
bearing  and  waste  its  possibilities,  while  a  method  adapted  to  a  vigor- 
ous vine  would  cause  a  weak  vine  to  attempt  to  bear  a  large  crop  of 
worthless  grapes  and  perhaps  die  in  the  'attempt. 

Certain  methods  of  pruning  may  result  in  an  abnormally  large 
crop  one  year,  though  usually  at  the  cost  of  quality.  Such  a  crop  is 
always  followed  by  a  small  one.  Alternate  bearing  of  this  kind  dimin- 
ishes the  average  crop  of  a  term  of  years.  The  neglected  possibilities 
of  one  year  can  be  utilized  by  the  vine  only  in  part  during  the  follow- 
ing year. 

Unless  the  pruner  can  distinguish  the  fruit  buds  he  may  fail  to 
leave  a  sufficient  number.  The  loss  from  this  cause  is  the  greater  the 
more  vigorous  the  vines,  and  greater  with  certain  varieties  than  with 
others. 

Bad  pruning  is  a  frequent  cause  of  inferior  quality.  When  the 
crop  is  too  large  for  the  vigor  of  the  vine,  or  even  of  a  part  of  the  vine, 
the  grapes  will  be  small,  will  fail  to  develop  sugar,  flavor,  or  color  and 
may  dry  up  or  sunburn  before  they  are  ripe.  Bad  pruning  results 


8  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

in  uneven  and  improper  distribution  of  the  grapes  on  a  vine.  This  is 
particularly  harmful  to  shipping  grapes,  and  results  in  uneven  ripen- 
ing and  coloring.  The  grapes  are  subjected  to  different  conditions  of 
light  and  heat  according  to  their  distance  from  the  ground  and  to  the 
degree  in  which  they  are  shaded  by  the  leaves  or  other  grapes. 

On  a  vine  of  unsuitable  form,  the  bunches  may  lie  on  the  ground 
and  be  contaminated  by  the  soil  and  subject  to  mildew  and  mold,  or 
they  may  be  entangled  with  each  other  or  with  the  canes,  making  it 
impossible  to  harvest  them  without  injury  or  loss. 

Not  only  is  the  crop  diminished  and  the  quality  injured  by  bad 
pruning  but  the  cost  of  production  is  increased. 

Vines  of  proper  and  uniform  shape  can  be  plowed,  cultivated,  and 
hoed  with  a  minimum  of  labor.  Such  vines  can  be  pruned  and  suck- 
ered  at  much  less  cost  than- irregular,  misshapen  vines.  The  control 
of  the  vine-hopper,  of  oidium,  and  of  other  diseases  is  more  difficult 
unless  the  vines  are  of  regular,  standard  shape. 

The  harvesting  of  the  grapes,  especially  of  shipping  grapes,  is  much 
simpler  and  more  satisfactory  if  the  vines  are  well  pruned.  The  cost 
of  trimming  and  the  loss  in  culls  are  much  diminished  and  the  ship- 
ping qualities  of  the  grapes  improved  by  proper  pruning. 

Finally,  the  useful  length  of  life  of  the  vineyard  depends  to  a  great 
extent  on  the  pruning.  Bad  pruning  not  only  results  in  large  pruning 
wounds  in  vital  parts  but  exposes  the  vine  to  serious  mechanical  in- 
juries from  the  implements  of  cultivation.  These  wounds  and  injuries 
afford  means  of  ingress  to  injurious  parasites,  borers  of  various  kinds, 
and  particularly  to  infection  by  black  knot  and  wood-rot  fungi.  Irreg- 
ularity of  bearing,  also,  not  only  makes  the  vine  more  susceptible  to 
attacks  of  this  kind  but  occasional  excessive  crops  may  actually  kill 
vines.  Certain  mistakes  in  pruning  favor  the  growth  of  suckers,  which 
appropriate  the  sap  and  cause  drying  up  and  final  death  of  the  crown 
and  trunk. 

HABIT  AND  CHARACTERISTICS  OF  THE  VINE 
Vitis  vimfera. — "With  a  few  unimportant  exceptions,  all  the  vines 
grown  for  their  fruit  in  California  are  varieties  of  Vitis  vinifera,  a 
plant  originating  apparently  in  the  region  south  of  the  Caucasus  but 
now  growing  wild  throughout  Western  Asia  and  the  Mediterranean 
countries  and  cultivated  wherever  the  climate  is  suitable. 

It  is  sometimes  called  the  European  vine  because  grown  in  Europe 
more  largely  than  elsewhere,  though  many  of  our  most  valuable  vari- 
eties originated  in  Asia  and  Northern  Africa.  The  varieties  are  some- 
times spoken  of  as  Californian  grapes  because  they  are  not  grown  east 
of  the  Rockies  or  to  any  great  extent  in  North  America  outside  of 


BULLETIN   241-246  VINE  PRUNING   IN    CALIFORNIA  9 

California.  They  include  all  the  varieties  of  vines  grown  in  California 
except  resistant  stocks  and  a  few  Labrusca  or  eastern  varieties,  such 
as  Concord  and  Pierce,  which  are  grown  to  a  limited  extent.  This 
difference  of  species  between  the  varieties  grown  in  the  eastern  states 
and  in  California  accounts  to  some  extent  for  the  differences  in  methods 
of  pruning,  though  the  difference  of  climate  is  an  equal  if  not  more 
important  factor. 

Vitis  vinifera  and  its  varieties,  like  all  true  vines,  are  sarmentose 
plants,  that  is,  they  possess  naturally  long,  slender,  flexible  trunks  in- 
capable of  self-support,  which  attach  themselves  by  means  of  tendrils 
to  trees  or  other  available  support.  If  allowed  to  grow  without  re- 
striction, they  will  grow  to  the  top  of  high  trees  in  a  manner  similar 
to  the  Vitis  Labrusca  of  the  eastern  states  or  the  ViUs  Calif ornica  of 
the  Pacific  states.  (See  cover  cut  and  Fig.  1.) 

In  vineyards,  the  natural  habit  of  the  vine  is  modified  to  a  remark- 
able extent,  principally  by  pruning.  Most  cultivated  vinifera  vines 
are  given  the  form  of  a  low  self-supporting  shrub  with  a  short,  rigid, 
vertical  trunk.  This  complete  change  of  natural  form  is  accomplished 
without  noticeable  injury  to  the  vigor  or  productive  capacity  of  the 
plant.  In  some  cases,  however,  it  may  be  carried  too  far  and  certain 
varieties  require  to  be  allowed  to  develop  in  a  somewhat  more  natural 
direction. 

Structure  of  a  Cultivated  Vine. — The  cultivated  vine  has  a  perma- 
nent framework,  consisting  of  root,  trunk,  and  arms,  producing  an 
annual  growth  of  shoots,  leaves,  and  fruit  above  ground,  and  of  root- 
lets below. 

The  root  and  its  branches  extend  in  all  directions  through  the  soil 
wherever  they  find  favorable  conditions.  Their  extent  is  limited  only 
by  the  competition  of  other  roots  or  by  mechanical  obstructions.  Their 
functions  are  to  collect  water  and  nutrient  salts  from  the  soil. 

The  trunk  is  usually  vertical,  but  may  be  in  part  horizontal.  It 
varies  in  length  from  one  to  two  feet  in  low  and  from  three  to  six  feet 
in  high  vines.  Its  functions  are  the  conduction  and  storage  of  food 
materials  and  the  support  of  leaves  and  fruit. 

The  arms  are  the  smaller  divisions  of  the  framework  attached  to 
the  trunk.  They  vary  in  length  from  a  few  inches  to  a  maximum  of 
about  eighteen  inches.  They  may  rise  radially  from  the  top  of  the 
trunk  (vase  form)  or  along  its  whole  length  (vertical  cordon].  They 
may  be  in  one  vertical  plane  at  the  top  of  the  trunk  (fan-shape)  or* 
along  the  whole  length  of  the  trunk  (horizontal  cordon).  Their  func- 
tions are  the  production  of  young  wood  and  the  proper  distribution  of 
leaves  and  fruit. 


10 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


The  young  wood  produced  each  year  by  the  arms  is  utilized  to  form 
the  spurs  and  canes  which  bear  the  leaves  and  fruit.    Its  total  length 


will  vary  in  different  cases  from  a  few  dozen  feet  to  several  hundred. 
In  mature  vines  from  90  per  cent  to  98  per  cent  of  all  the  growth  is 
removed  at  each  pruning. 


BULLETIN  241-246  yiNE  PRUNING   IN   CALIFORNIA  11 

In  order  to  discuss  pruning  intelligently,  it  is  necessary  to  agree  on 
the  definition  of  the  technical  terms  used.  The  terms  and  definitions 
employed  here  are  in  nearly  all  cases  those  used  by  the  majority  of 
Californian  grape  growers.  An  attempt  has  been  made  to  have  them 
correspond  as  nearly  as-  possible  to  the  terms  used  in  other  countries 
and  in  the  pruning  of  other  plants.  The  main  difficulty  in  this  respect 
has  been  with  the  terms  spur,  sucker,  water-sprout,  and  lateral.  In 
these  eases  the  usage  of  the  majority  of  Californian  grape  growers  has 
been  followed. 


TERMS  EEFEREING  TO  THE  FORM  AND  STRUCTURE  OF  A  CULTIVATED 

VINE 

SUBTERRANEAN  PARTS 

Root  Tips.    The  extreme  ends  of  the  rootlets. 

Rootlets.    The  finest  roots,  the  growth  of  one  season.     (Fibrous  roots.) 

Root  Branches.  All  the  divisions  and  subdivisions  of  the  main  roots 
older  than  one  season. 

Main  Roots.  The  main  root  branches  arising  from  the  underground 
stem  or  tap  root. 

Tap  Root.  A  single  plunging  main  root  or  prolongation  of  the  under- 
ground stem. 

Root  Crown.  The  base  of  the  underground  stem  or  region  from  which 
originate  the  main  roots. 

Underground  Stem.  The  part  of  the  trunk  below  ground  from  the 
bottom  of  which  start  the  main  roots  or  tap  root. 

AERIAL  PARTS.     (A)  SKELETON  OP  FRAMEWORK  AFTER  PRUNING 
Trunk  or  Stem.    The  unbranched  body  of  the  vine. 
Head  or  Crown.    The  top  of  the  trunk  or  region  from  which  arise  the 

arms  or  branches. 
Branches.     The  main  division  (when  long)  of  the  trunk.     Branches 

bear  arms. 
Arms.     The  main  divisions  (when  short)  of  the  trunk  or  branches. 

Arms  bear  spurs. 

Spurs.    Short  pieces  of  the  bases  of  canes,  1  to  4  nodes  with  their  eyes. 
Fruit  Spurs.    Spurs  left  for  the  production  of  fruit. 
Wood  Spurs,     (a)  Renewal  Spurs.    Spurs  left  to  supply  fruit  spurs, 
or  fruit  canes  for  the  following  year,  1  to  2  eyes. 

( b )  Replacing  Spurs.    Spurs  left  to  supply  growth  for  the  replac- 
ing of  defective  arms,  1  eye. 
Fruit  Canes.    Canes  left  for  fruit,  iy2  to  6  feet  long. 


12  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

AERIAL  PARTS.    (B)  ANNUAL  GROWTH 

1.  Before  the  formation  of  leaves 
Eyes.    The  compound  buds  on  the  canes. 

Fruit  Buds.  Buds  from  which  a  shoot,  bearing  flowers,  will  be  pro- 
duced. 

Wood  Buds.    Buds  from  which  sterile  shoots  will  be  produced. 

Base  Bud.    The  lowest  well  formed  eye  at  the  base  of  a  cane  or  spur. 

Latent  Buds.  Buds  which  have  remained  dormant  for  one  growing 
season  or  more. 

Adventitious  Buds.    Buds  arising  from  leafless  parts  of  the  wood. 

Main  Buds.    The  large  central  buds  of  the  eyes. 

Secondary  Buds.    The  small  lateral  buds  of  the  eyes. 

2.  During  the  formation  of  leaves 
Shoots.    The  succulent  growth  arising  from  a  bud. 
Fruit  Shoots.    Shoots  bearing  flowers. 

Sterile  Shoots.    Shoots  not  bearing  flowers. 

Water-sprouts.    Shoots  arising  from  dormant  or  adventitious  buds. 
Suckers.    Shoots  originating  below  the  surface  of  the  ground. 
Laterals.     Secondary  shoots  arising  from  buds  in  the  axils  of  the 
leaves  of  the  main  shoots. 

3.  After  the  fall  of  the  leaves,  before  pruning 

Old  Wood.    Parts  of  the  vine  older  than  one  year. 

Canes.  Young  wood  or  growth  of  the  current  season,  consisting  of  a 
series  of  nodes,  each  furnished  with  an  eye  and  separated  by  the 
smooth  portions  called  internodes. 

Fruit  Wood.  Canes  with  fruit  buds,  usually  growing  out  of  two-year- 
old  wood. 

Sterile  Wood.  Canes  without  fruit  buds.  Those  growing  out  of  wood 
older  than  two  years  are  usually  unfruitful. 

Roots. — The  pruner  has  little  to  do  with  the  roots  except  when 
planting  or  in  cases  where  it  is  advisable  to  remove  certain  roots  of 
young  vines,  either  because  they  arise  from  the  scion  above  the  union 
or  because  they  are  too  near  the  surface.  Regular  root  pruning  at 
intervals  of  several  years  is  practiced  in  some  regions,  but  there  seems 
to  be  no  sufficient  reason  for  the  practice  in  California.  Some  of  the 
pruner 's  operations  on  the  above-ground  portions  of  the  vine,  however, 
may  promote  or  restrict  root  growth. 


BULLETIN  241-246          VINE  PRUNING  IN  CALIFORNIA  13 

Every  year  the  vine  makes  a  new  growth  of  rootlets,  and  these  root- 
lets are  its  sole  means  of  obtaining  water  and  soil  nutrients.  These  it 
absorbs  by  means  of  the  young  cells  and  root  hairs  within  an  inch  or 
two  of  the  root  tips.  The  rest  of  the  root  system  serves  to  conduct  the 
absorbed  material  to  the  aerial  parts  of  the  vine,  to  store  reserve 
material  for  spring  growth,  and  to  hold  the  vine  in  place.  The  posi- 
tion, number,  and  vigor  of  the  roots  depend  more  on  the  nature  of  the 
soil  and  cultural  operations  than  on  anything  the  pruner  can  do. 

The  amount  of  root  growth  and  that  of  top  growth  are  mutually 
dependent.  Conditions  or  methods  which  stimulate  one  stimulate  the 
other  and  we  can  not  curtail  one  without  diminishing  the  other.  The 
position  of  the  root  system  is  due  partly  to  the  nature  of  the  variety  or 
species  of  vine  and  partly  to  the  conditions  of  penetrability,  moisture, 
aeration,  and  food  supply  of  the  soil.  The  roots  will  go  where  the  con- 
ditions are  most  favorable,  and  nothing  we  can  do  that  does  not  change 
these  conditions  will  affect  the  position  of  the  roots  except  temporarily. 
The  rootlets  of  a  vine  grown  from  a  short  cutting  will  finally  occupy 
exactly  the  same  position  in  the  soil  as  those  of  a  vine  grown  from  a 
long  cutting. 

We  can,  to  some  extent,  influence  the  position  of  the  main  roots  by 
appropriate  treatment  of  the  vine  when  young.  No  main  roots  should 
arise  nearer  than  four  or  five  inches  from  the  surface  or  they  will  be 
in  danger  of  injury  from  the  plow.  The  danger  of  shallow  rooting  is 
greatest  in  irrigated  soils,  and  can  be  avoided  by  infrequent  and  deep 
irrigations,  by  avoiding  a  continually  wet  surface  in  the  growing  season 
during  the  first  two  years,  and,  when  necessary,  by  removing  the  sur- 
face roots  while  they  are  small. 

The  best  root  system  is  that  in  which  all  the  main  roots  arise  from 
the  root  crown  at  the  bottom  of  the  underground  stem.  This  does  not 
prevent  the  utilization  of  soil  at  higher  levels,  for  rootlets  will  grow 
into  all  regions  of  the  soil  where  the  conditions  are  favorable,  whether 
below  or  above  the  main  roots.  No  injury  need  be  apprehended  from 
the  plowing  up  of  small  rootlets,  as  they  will  reform  as  fast  as  needed. 
The  destruction  of  a  main  root,  however,  is  harmful,  as  it  not  only 
destroys  all  the  rootlets  by  means  of  which  the  root  was  feeding  the 
vine  but  the  large  wound  may  allow  decay  organisms  to  attack  the  vine. 

The  supposed  superiority  of  a  tap  root  is  a  mere  superstition,  except 
in  so  far  as  it  involves  a  perfect  continuity  of  healthy  tissue  from 
trunk  to  root  branches.  Two,  three,  or  more  main  roots  from  the  root 
crown  are  equally  effective,  providing  there  are  no  unhealed  wounds 
on  the  underground  stem  to  be  attacked  by  boring  insects  or  decay 
fungi.  (See  Fig.  2.) 


14 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


In  wet  soils  there  is  usually  a  definite  root  crown  at  6  to  8  inches 
below  the  surface.  The  planting  of  a  long  "cutting  will  not  alter  this 
condition,  as  the  roots  simply  start  where  the  moisture,  temperature, 


Fig.  2. — Boot  crown  of  a  four-year-old  vine. 

and  aeration  are  most  favorable,  and  all  below  this  point  dies.  In 
drier  soils  a  short  cutting  will  make  a  similar  root  crown,  but  on  a 
longer  cutting  the  main  roots  may  arise  at  various  levels.  There  is  no 
objection  to  the  latter  form  of  branching,  providing  some  roots  start 
at  the  bottom  of  the  cutting  and  completely  heal  the  surface.  A  root 
crown  at  the  surface  of  the  ground  is  very  objectionable,  as  it  is  very 


BULLETIN  241-246  VINE  PRUNING   IN    CALIFORNIA  15 

subject  to  injury  from  plow  and  hoe,  and  consequently  subject  to 
infection  by  black  knot  and  wood  rot  fungi.  It  also  makes  clean  culti- 
vation and  the  perfect  and  economical  removal  of  suckers  difficult.  A 
clean,  smooth,  healthy  underground  stem  of  at  least  six  inches  is  very 
desirable. 

The  Trunk.  The  trunk  is  the  body,  we  might  almost  say  the  life, 
of  the  vine.  Its  main  functions  are  to  support  the  bearing  wood  at 
the  right  height  from  the  ground,  to  carry  water  and  nutrient  salts 
from  the  roots  to  the  leaves  and  elaborated  food  from  the  leaves  to  the 
roots.  On  its  continued  healthy  state  depend  the  vigor,  crop,  and  long 
life  of  the  whole  vine.  It  is  a  continuation  of  the  underground  stem 
and  should  be  perfectly  straight,  smooth,  and  without  wound,  branch, 
or  cane  from  the  ground  to  the  head.  Its  length  or  height  depends 
on  the  variety,  climate,  and  form  of  pruning,  but  should  in  all  cases 
be  sufficient  to  allow  of  close  cultivation,  easy  hoeing,  and  proper 
suckering.  This  means  a  minimum  of  about  ten  inches.  Except  in 
certain  forms  of  trellis  and  cordon  pruning,  it  should  never  exceed 
thirty  inches.  A  greater  height  is  expensive  to  develop  and  sustain, 
and  gives  no  corresponding  advantage. 

The  trunk  is  formed  during  the  first  three  years  of  the  life  of 
the  vine.  Defects  acquired  during  this  period  can  never  be  wholly 
remedied. 

The  Head  of  the  vine  is  the  top  of  the  trunk  or  region  from  which 
the  arms  start.  At  first  it  is  more  or  less  indefinite,  the  spurs  from 
which  the  arms  finally  develop  being  at  heights  varying  six,  eight,  or 
more  inches,  but  none  nearer  than  six  inches,  from  the  surface  of  the 
ground.  As  the  vine  develops  the  arms  are  gradually  brought  to  prac- 
tically the  same  level  by  the  removal  of  ill-placed  arms  before  they 
become  large,  and  a  definite  head  is  thus  formed  at  the  desired  height. 

Branches  or  long  major  divisions  of  the  trunk  are  not  used  in  any 
of  the  forms  of  pruning  adopted  in  California.  Their  only  use  is  for 
certain  forms  of  high  trellises  or  for  covering  an  arbor.  "Where  the 
trunk  is  simply  elongated  without  branching  or  has  only  two  horizontal 
branches  at  the  same  level,  the  form  is  called  a  cordon.  In  these  forms 
there  is  no  proper  head  or  crown. 

The  Arms  are  the  final  divisions  of  the  body  of  the  vine  and  bear 
the  spurs  and  fruit  canes.  They  should  be  long  enough  to  spread  the 
crop  so  as  to  give  all  the  bunches  the  necessary  sun,  space,  and  air  to 
develop  properly.  They  should  not  be  long  enough  to  interfere  with 
cultivation  nor  to  be  in  danger  from  the  use  of  implements.  The  more 
vigorous  the  vine  and  the  higher  the  trunk,  the  longer  the  arms  should 
be.  The  correct  length  will  vary  from  six  to  eighteen  inches. 


16 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


The  arras  constantly  tend  to  become  too  long,  and  it  requires  skill, 
knowledge,  and  foresight  on  the  part  of  the  primer  to  keep  them  within 
the  required  limits.  Long  arms  tend  to  become  weak  and  unfruitful 
and  must  periodically  be  replaced  by  new  arms  developed  from  as  near 
the  head  of  the  vine  as  possible. 


Fig.  3. — Carignane  vine  fifteen  years  old.  Well  formed  trunk,  head  and 
arms;  short  spurs. 

The  number  of  the  arms  will  depend  on  the  style  of  pruning 
adopted  and  on  the  size  of  the  vine.  With  very  short  pruning,  the 
number  on  a  mature  vine  will  vary  from  three  or  four  on  a  small 
growing  variety  in  poor  soil  to  ten  or  fifteen  with  very  vigorous  vines. 
With  longer  pruning,  the  number  of  arms  is  correspondingly  decreased, 
and  with  long  or  cane  pruning,  two  to  four  arms  are  all  that  should 
be  given. 

The  arrangement  of  the  arms  depends  principally  on  the  planting 
plan  and  method  of  cultivation.  When  the  vines  are  approximately 
equidistant  in  both  directions  and  cross-cultivation  is  practiced,  the 
arms  should  be  arranged  as  symmetrically  as  possible  in  ' '  vase-form. ' ' 


BULLETIN   241-246  yiNE   PRUNING    IN    CALIFORNIA  17 

When  the  vines  are  planted  closer  together  in  rows  with  wider  "ave- 
nues" between  them,  especially  when  trellised,  cross-cultivation  is  im- 
possible. In  these  cases  it  is  of  great  importance  that  the  arms  should 
be  "fan-shaped,"  that  is,  arranged  in  a  single  plane.  This  makes  it 
possible  to  plow  and  cultivate  very  close  to  the  vine  and  even  to  cut 
out  some  of  the  ridge  between  the  vines  with  horse  hoes  or  cultivators. 
Care  in  shaping  the  young  vines  properly  in  this  respect  will  obviate 
a  great  deal  of  expensive  hand  hoeing  when  the  vines  are  large.  The 
formation  of  the  arms  takes  place  principally  during  the  third  and 
fourth  years,  and  mistakes  made  at  this  time  can  be  remedied  only 
imperfectly  later  and  then  at  the  cost  of  mutilating  the  vine.  Trellised 
vineyards  carelessly  pruned  in  this  respect  often  have  a  strip  two  feet 
wide  along  each  row  to  be  worked  by  hand.  This  strip  can  be  reduced 
to  six  inches  or  less  by  carefully  forming  the  vines  when  young. 

At  and  near  the  ends  of  each  arm  are  left  pieces  of  young  wood 
called  Spurs  or  Fruit  Canes,  according  to  their  length.  The  spurs 
vary  in  length  according  to  their  purpose.  In  ordinary  short  pruning 
most  of  the  spurs  are  expected  to  produce  fruit.  Only  fruit  wood, 
that  is,  canes  growing  out  of  two-year-old  wood,  therefore,  should  as 
a  rule  be  used  for  this  purpose.  The  average  length  of  a  fruit  spur 
is  two  nodes,  which  will  give  three  eyes  counting  the  base  bud  situated 
at  the  base  of  the  cane  or  separated  only  by  a  very  short  node,  which  is 
not  counted.  Fruit  spurs  will  vary  in  length,  however,  from  one  node 
to  four,  according,  principally,  to  the  vigor  and  size  of  the  cane.  The 
larger  the  cane  the  more  eyes  are  left  on  the  spur  it  furnishes. 

A  Renewal  Spur  is  not  left  primarily  for  fruit.  Its  purpose  is  to 
furnish  shoots  from  which  the  fruit  spurs  and  fruit  canes  are  formed 
the  following  year.  In  ordinary  short  pruning,  the  fruit  spurs  func- 
tion at  the  same  time  as  renewal  spurs.  In  long  pruning,  one  or  two 
renewal  spurs  must  be  left  below  each  fruit  cane  to  supply  fruit  canes 
for  the  following  year.  Such  spurs  usually  consist  of  two  full  inter- 
nodes,  but  in  some  cases  they  may  be  reduced  to  a  single  node  with  two 
eyes,  including  the  base  bud.  As  renewal  spurs  are  not  intended  for 
fruit,  only  a  sufficient  number  should  be  left  to  insure  enough  properly 
placed  canes  for  the  next  pruning.  This  number  will  be  the  same  as 
the  number  of  fruit  canes  with  one,  two,  or  three  extra  per  vine  to 
provide  against  the  failure  of  some  and,  when  necessary,  for  an  in- 
creased number  of  fruit  canes  the  following  year.  Sterile  or  fruit 
wood  may  be  used  for  this  purpose,  as  either  will  produce  fruit  wood 
for  the  following  year. 

The  function  of  a  Replacing  Spur  is  to  provide  for  the  shortening 
or  replacing  of  an  over-elongated  or  otherwise  defective  arm.  It  con- 


18 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


sists  of  only  one  internode  and  its  eye,  or  even  of  simply  the  base  bud, 
if  this  is  well  formed.  As  it  is  intended  to  replace  an  arm,  it  is  chosen 
as  near  the  base  of  this  arm  as  is  practicable  without  necessitating  too 
large  a  wound  when  the  arm  is  removed.  Unless  the  arm  is  very  de- 
fective, its  removal  is  deferred  until  the  year  following  that  in  which 
the  replacing  spur  is  left.  In  this  way  no  crop  is  sacrificed.  The  first 
year  the  crop  is  borne  as  usual  on  spurs  or  canes  at  the  end  of  the  arm. 
The  next  year  the  replacing  spur  has  produced  fruit  wood  from  which 


Fig.  4. — Muscat  vine,  over  fifteen  years  old.     Trunk  too  short,  arms  too  long, 
but  head  of  good  form. 

can  be  formed  a  fruit  spur  which  in  turn  develops  into  a  new  arm. 
A  replacing  spur  consists  always  of  sterile  wood,  as  it  is  made  from  a 
cane  growing  out  of  old  wood  near  the  base  of  the  arm.  Replacing  of 
arms  should  be  done  with  sufficient  frequency  to  avoid  making  the 
very  large  wounds  that  would  be  necessary  if  the  arms  were  allowed 
to  become  very  old  and  large.  Spurs  intended  to  produce  new  arms 
on  developing  young  vines  are  left  longer  and  usually  consist  of  fruit 
wood,  as  they  function  as  fruit  spurs  at  the  same  time. 

Some  varieties  of  vines  will  not  bear  satisfactory  crops  on  spurs, 
owing  to  the  sterility  of  the  buds  near  the  base  of  the  cane  or  to  the 
small  size  of  the  bunches,  which  makes  it  difficult  to  obtain  a  sufficient 


BULLETIN  241-246 


VINE   PRUNING    IN    CALIFORNIA 


19 


number  from  spurs  to  constitute  a  full  crop.  In  such  cases  it  is  neces- 
sary to  adopt  some  form  of  long  pruning,  with  fruit  canes.  A  fruit 
cane  is  a  piece  of  the  current  year's  fruit  wood  from  one  and  one-half 
to  six  feet  long.  These  canes  should  be  taken,  wherever  possible,  from 
canes  growing  out  of  two-year-old  wood,  in  order  to  increase  the  proba- 
bility of  the  buds  being  fruitful.  Fruit  buds  may  occur  on  water- 
sprouts  more  or  less  abundantly,  according  to  the  variety,  age,  and 
condition  of  the  vine,  but  are  nearly  always  much  more  abundant  on 
"fruit  wood."  Canes  less  than  two  feet  long  are  not  advisable,  as 
they  are  difficult  to  attach  to  the  stake  or  trellis  without  breaking. 
No  advantage,  on  the  other  hand,  is  obained  from  fruit  canes  longer 


Fig.  5. — Cross-section  through  vine 
two  or  three  lateral  secondary  buds. 


:eye"  showing  central  main  bud  and 


than  six  feet.  Fruit  canes  six  feet  long  will  produce  as  many  fruiting 
shoots  as  the  vine  can  develop  properly.  Longer  canes,  indeed,  usually 
fail  to  develop  any  more  fruit,  as  a  larger  proportion  of  the  buds  fail 
to  start,  and  even  when  more  start  the  fruit  is  apt  to  be  inferior  in 
size  and  quality.  Four  six-foot  fruit  canes  with  five  or  six  renewal 
spurs  is  about  the  maximum  for  the  strongest  vines  with  our  methods 
of  planting.  More  than  this  may  sometimes  increase  the  crop,  but 
nearly  always  at  the  expense  of  quality  and  often  with  great  danger 
of  injurying  the  vine  by  over-bearing.  This  latter  danger  is  particu- 
larly to  be  feared  with  vines  grafted  on  resistant  stock. 

The  buds  on  the  canes  are  usually  called  Eyes  by  the  pruner.  This 
is  a  convenient  term,  as  they  are  more  than  simple  buds,  and  consist 
of  a  main  central  bud  with  one  or  two  smaller  secondary  buds  within 
the  same  bud  scales.  (See  Fig.  5.) 


20  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

The  external  appearance  of  all  the  eyes  on  a  vine  is  similar.  They 
differ,  however,  in  the  important  respect  that  some  are  capable  of 
producing  a  fruit-bearing  shoot  and  others  are  not.  The  former  are 
called  Fruit  Buds,  the  latter  sterile  or  Wood  Buds.  If  a  thin  section 
of  a  bud  is  examined  under  a  low-power  microscope,  it  is  possible  to 
determine  its  character.  The  embryo  blossom  bunches  can  be  seen  in 
the  fruit  buds.  ( See  Figs.  5,  6. ) 

There  is  no  external  difference  in  appearance  between  fruitful  and 
sterile  buds,  and  the  pruner  has  no  means  of  determining  with  cer- 
tainty whether  an  eye  contains  the  possibility  of  fruiting  or  not.  He 
can,  however,  tell  what  the  relative  probability  of  fruitfulness  is  with 


Fig.   6. — Cross-section   through   fruit   bud   showing   two   embryonic   blossom 
bunches. 

different  eyes,  which,  for  this  purpose,  is  all  that  is  necessary.  This 
he  determines  by  the  position  of  the  eye  relative  to  the  cane  and  the 
vine.  The  greatest  probability  of  fruitfulness  occurs  in  the  eyes  of 
canes  which  have  been  produced  by  the  spurs  of  the  previous  year. 
Or,  as  the  pruner  expresses  it,  the  fruit  buds  are  on  the  canes  growing 
out  of  two-year-old  wood.  Canes  produced  by  older  wood,  that  is, 
which  have  grown  from  dormant  or  adventitious  buds,  are  usually 
sterile. 

The  position  of  the  eye  on  the  cane  is  also  of  importance  in  judging 
its  probability  of  fruitfulness.  The  base  bud  is  usually  sterile.  The 
first  and  second  eyes  are  usually  fruitful  with  most  vinifera  varieties. 
With  some  varieties  the  probability  of  fruitfulness  is  not  great  until 
we  reach  the  fourth  or  fifth  eye.  Beyond  this  point  the  eyes  are 
usually  fruitful  until  we  reach  a  point  where  the  cane  is  imperfectly 


BULLETIN    241-246  VINE   PRUNING    IN    CALIFORNIA  21 

developed  or  badly  matured.    Sterility  of  the  lower  buds  makes  long 
pruning  necessary. 

A  bud  may  be  fruitful  in  varying  degrees.    A  thoroughly  fruitful 
bud  of  most  vinif  era  varieties  will  produce,  on  the  average,  two  bunches 


Fig.   7. — Longitudinal  section  of  a  fruit  bud  showing  an   embryonic   shoot 
with  embryonic  leaves  and  blossom  bunch. 

of  grapes  of  full  normal  size.  The  number  may  be  one,  two,  or  three, 
according  to  variety.  A  less  fruitful  bud  will  produce  fewer  and 
smaller  bunches.  This  reduction  of  fruitfulness  may  continue  until 


Fig.  8. — Longitudinal  section  of  a  sterile  bud. 

we  find  buds  producing  bunches  which  are  little  more  than  tendrils 
with  a  few  grapes.  Such  buds  are  practically  sterile,  producing  few 
blossoms  or  grapes.  Their  bunches  are  easily  distinguished  from  the 
loose  bunches  due  to  the  dropping  of  the  blossoms  without  setting. 


22  UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 

Wood  Buds  are  those  which  contain  no  rudiments  of  blossoms  and 
are  therefore  incapable  of  yielding  fruit.  They  are  distinguished  by 
their  position,  which  can  be  inferred  from  what  has  been  said  regarding 
the  position  of  fruit  buds.  They  occur  principally  on  water-sprouts, 
and  include  usually  also  base,  dormant,  and  adventitious  buds. 

Some  of  the  buds  left  on  a  vine  do  not  develop  the  first  year,  or 
produce  only  a  few  small  leaves.  Such  cases  are  particularly  frequent 
in  long  pruning.  These  buds  will  often  develop  the  second  year, 
especially  if  shorter  pruning  is  adopted.  These  buds  are  called  dor- 
mant or  latent  buds,  and  are  usually  sterile. 

"With  the  warm  weather  of  spring  the  bud  commences  to  swell,  then 
to  elongate,  and  finally  produces  a  growing  shoot,  which  pushes  through 
the  bud  scales.  This  shoot  is  produced  by  the  main  bud.  If  the  vine 
is  vigorous  and  the  number  of  buds  limited,  one  or  both  of  the  secondary 
buds  may  start  and  produce  smaller  shoots.  An  injury  to  the  main 
bud  results  in  the  starting  of  the  secondary  buds.  Cut  worms  or  other 
gnawing  insects  often  kill  the  main  bud  without  injurying  the  others. 
The  same  effect  may  be  produced  by  a  moderate  frost  after  the  shoots 
have  started.  A  heavy  spring  frost  will  sometimes  kill  all  the  buds  in 
a  started  eye. 

The  main  buds  on  fruit  wood  usually  produce  fruit-bearing  shoots. 
The  rudimentary  blossom  bunches  can  be  seen  after  the  shoot  has 
grown  a  few  inches.  There  are  usually  two,  or  more  rarely  one  or 
three.  They  may  occur  at  the  second  and  third,  the  third  and  fourth, 
or  the  fourth  and  fifth  nodes.  ( See  Fig.  9. )  Shoots  from  the  second- 
ary buds  may  also  produce  fruit,  but  the  bunches  are  smaller  and  less 
numerous. 

A  shoot  coming  from  a  dormant  or  adventitious  bud  on  the  old 
wood  is  called  a  water-sprout,  and  is  usually  sterile.  A  sucker  is  a 
shoot  coming  from  below  the  ground.  On  vines  which  are  properly 
handled  the  suckers  are  removed  carefully  and  completely  every  year, 
so  that  few  are  produced,  and  as  these  must  come  from  adventitious 
buds  they  are  sterile.  If  the  removal  of  suckers  is  neglected  or  im- 
perfect, a  shoot  below  ground  may  arise  from  the  base  of  a  sucker  of 
the  previous  year,  in  which  case  it  may  be  fruitful. 

As  a  shoot  grows  it  produces  one  leaf  at  each  node  on  alternate 
sides.  Opposite  the  second,  third,  fourth,  or  fifth  leaf  is  produced  a 
blossom  bunch  on  fruit  shoots  and  a  tendril  on  sterile  shoots.  The 
next  one  or  two  nodes  may  also  produce  bunches  or  tendrils.  As  the 
shoot  elongates  further  it  produces  more  tendrils,  but  not  at  all  nodes 
in  vinifera  varieties.  Every  third  node  is  usually  without  a  tendril. 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


23 


In  the  axil  of  the  leaf,  that  is,  in  the  angle  between  the  leaf  stalk 
and  the  shoot,  occurs  a  bud.  Beside  this  bud  very  often  arises  a  side 
shoot  called  a  lateral.  These  laterals  may  be  short  or  may  grow  long 
and  form  large  lateral  canes.  Any  injury  to  the  growing  tip  of  the 
main  shoot  stimulates  the  production  and  growth  of  laterals.  Laterals 


Fig.  9. — Blossom-bearing  shoot  of  Tokay  vine. 

of  some  varieties  may  produce  fruit  like  main  canes.  This  fruit  is  the 
so-called  second  crop,  and  is  usually  about  two  weeks  later  than  the 
main  crop.  Rarely  these  laterals  may  produce  secondary  laterals  in 
their  turn,  which  in  a  few  varieties  may  produce  a  third  crop.  (See 
Fig.  10.) 

We  have  on  a  vine,  therefore,  fruit  wood  and  sterile  wood,  but  this 
distinction  is  not  absolute.    Some  of  the  buds  on  the  fruit  wood  may 


24 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


be  sterile,  while  some  on  the  sterile  wood  may  be  fruitful.  The  proba- 
bilities of  fruitfulness,  however,  are  so  much  greater  in  one  case  than 
in  the  other  that  the  pruner  may  safely  proceed  as  though  it  were 
absolute.  Moreover,  with  proper  pruning  little  sterile  wood  is  pro- 
duced. The  difference  between  the  two  kinds  of  wood  varies  greatly 
with  different  varieties.  On  a  Muscat  of  Alexandria  most  of  the  buds, 


Fig.  10. — Fruit-bearing  cane  of  Black  Morocco,  showing  (I)  first  crop,  (II) 
second  crop,  and  (III)  third  crop. 

even  on  water-sprout  canes,  contain  rudiments  of  blossoms.  The  fruit- 
fulness  of  all  kinds  of  wood,  moreover,  depends  on  weather,  soil,  and 
cultural  conditions.  In  some  cases  the  conditons  are  so  favorable  to 
fruitfulness  that  even  the  water-sprouts  bear.  Hot  summers,  certain 
mechanical  injuries  to  the  vine,  and  grafting  on  certain  stocks  have  a 
tendency  to  increase  the  proportion  of  fruit  buds  on  all  kinds  of  canes. 
On  the  other  hand,  cool  summers,  excessive  growth  of  vine  due  to  over- 
abundance of  water,  or  nitrogen  in  the  soil  may  cause  buds  in  all 
positions  to  be  mostly  sterile. 


BULLETIN  241-246  VINE  PRUNING   IN    CALIFORNIA  25 

THE  PRINCIPLES  OF  PRUNING 

Physiological  Principles. — The  correct  pruning  of  the  vine  is  based 
on  certain  facts  regarding  plant  growth  and  nutrition  which  the  pruner 
should  understand.  Some  of  these  facts  apply  to  all  plants;  others 
are  peculiar  to  the  vine. 

1.  The  vine  prepares  its  food  by  means  of  the  green  coloring  matter 
(chlorophyll)  of  its  leaves.    All  the  sugar,  starch,  and  other  substances 
which  make  up  the  body  of  the  vine,  and  those  of  its  crop,  are  elabor- 
ated in  the  leaves  by  means  of  the  chlorophyll  under  the  influence  of 
sunlight.    Carbon  dioxide  from  the  air  and  water  from  the  soil  furnish 
the  main  bulk,  while  the  mineral  salts  from  the  soil  furnish  a  smaller 
but  equally  necessary  part.    A  certain  area  of  green  leaf  surface  func- 
tioning for  a  certain  time  is  necessary  to  produce  sufficient  nourishment 
for  the  vital  needs  of  the  vine  and  for  the  production  of  the  crop. 
Those  leaves  most  exposed  to  the  direct  rays  of  the  sun  are  most  active 
in  absorbing  and  producing  food.    The  youngest  leaves  take  all  their 
nourishment  from  the  older  parts  of  the  plant ;  somewhat  older  leaves 
use  up  more  nutrient  material  than  they  absorb  from  the  air.     A 
young  shoot  may  thus  be  looked  on  as,  in  a  sense,  parasitic  upon  the 
rest  of  the  vine.    After  a  certain  stage,  the  leaves  produce  more  food 
material  than  they  utilize,  and  the  excess  goes  to  support  other  parts. 
The  true  feeders  of  the  vine  and  of  its  crop,  therefore,  are  the  mature, 
dark  green  leaves. 

This  principle  shows  that  any  method  which  forces  an  unnecessary 
growth  of  young  shoots  or  removes  mature  leaves,  while  still  active, 
limits  the  possibilities  of  production  both  of  wood  and  of  fruit. 

2.  Within  certain  limits  the  tendency  to  fruitfulness  of  a  vine  or 
a  part  of  a  vine  is  inversely  proportionate  to  its  vegetative  vigor. 
Within  these  limits,  methods  which  increase  the  vegetative  vigor  dimin- 
ish bearing,  and,  vice  versa,  methods  which  diminish  vigor  increase 
bearing.    Failure  to  reckon  with  this  fact  and  to  maintain  a  proper 
mean  between  the  two  extremes  leads,  on  the  one  hand,  to  comparative 
sterility  and,  on  the  other,  to  over-bearing  and  premature  exhaustion 
of  the  vine. 

The  correct  treatment  of  a  vine  is  that  which  invigorates  it  as  much 
as  is  possible  without  diminishing  the  crop. 

3.  Other  conditions  being  equal,  an  excess  of  foliage  is  accompanied 
by  a  small  amount  of  fruit,  an  excess  of  fruit  by  diminished  foliage. 
This  and  No.  4  are  corollaries  of  Principle  No.  2. 

4.  Bending,  twisting,  or  otherwise  injurying  the  tissues  of  the  vines 
or  of  its  parts  tend  to  diminish  its  vegetative  vigor  and,  therefore, 
unless  excessive,  to  increase  its  fruitfulness. 


26  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

5.  The  vine  tends  to  force  out  terminal  buds  and  to  expend  most 
of  its  energy  on  the  shoots  farthest  from  the  trunk.    To  keep  the  vine 
within  practical  limits,  this  tendency  must  be  controlled  by  the  re- 
moval of  terminal  buds  or  by  measures  which  check  the  flow  of  sap 
and  force  the  growth  of  buds  nearer  the  stock. 

Certain  defective  styles  of  pruning  fail  to  recognize  this  tendency, 
and  are  therefore  impracticable  and  can  not  be  continued  indefinitely. 
One  of  the  commonest  of  these  is  the  tying  of  fruit  canes  vertically  to 
a  stake. 

6.  The  nearer  a  shoot  or  cane  approaches  the  vertical  the  more 
vigorous  it  will  be. 

This  principle  is  made  use  of  in  the  Guyot  and  similar  systems  of 
pruning.  The  shoots  from  renewal  spurs  are  tied  up  vertically  to  a 
stake  and  are  thus  rendered  vigorous.  On  the  other  hand,  the  fruit 
canes  are  tied  horizontally  to  wires,  thus  moderating  the  vigor  and 
increasing  fruitfulness. 

7.  The  size  of  vines  or  parts  of  vines  is  inversely  as  their  number, 
if  other  conditons  remain  the  same. 

Thus  the  fewer  vines  to  the  acre  the  larger  each  will  grow;  the 
fewer  shoots  allowed  to  grow  on  a  vine  or  the  arm  of  a  vine  the  larger 
each  individual  shoot.  This  principle  extends  to  the  fruit.  If  we  want 
large  bunches,  we  must  limit  their  number ;  if  we  want  large  berries, 
there  must  not  be  too  many  on  a  bunch. 

Winter  Pruning. — The  principal  pruning  of  the  vine  is  done  while 
the  plant  is  dormant,  between  the  fall  of  the  leaves  at  the  beginning 
of  winter  and  the  starting  of  the  buds  at  the  beginning  of  spring.  In 
large  vineyards  it  may  be  necessary  to  spread  the  pruning  over  most 
of  this  period ;  in  smaller  vineyards  it  is  usually  possible  to  prune  in 
the  month  which  is  judged  most  favorable. 

Season. — In  deciding  on  the  best  time  for  pruning  we  must  con- 
sider the  convenience  of  other  cultural  operations  and  the  effect  of  the 
period  on  the  health  and  bearing  of  the  vine. 

For  convenience,  the  earlier  the  pruning  is  done  the  better.  Prun- 
ing in  November  or  December  gives  abundant  time  to  gather  and  to 
remove  the  prunings,  to  apply  fertilizers,  to  plow,  irrigate,  and  sucker 
and  to  tie  up  the  fruit  canes  before  the  starting  of  the  buds. 

The  effects  of  the  time  of  pruning  on  the  vigor  and  fruitfulness  of 
the  vine  bear  a  close  relation  to  the  location  and  amount  of  reserve 
food  material  in  the  various  parts  of  the  plant. 

During  the  summer  the  leaves  feed  the  canes,  trunk,  and  roots. 
Just  before  the  natural  fall  of  the  leaves  the  canes  contain  the  maxi- 
mum amount  of  food  material,  viz.,  starch,  sugar,  cellulose,  and  other 


BULLETIN    241-246  VINE   PRUNING   IN    CALIFORNIA  27 

carbohydrates.  For  two  or  three  weeks,  immediately  following  the 
fall  of  the  leaves,  much  of  these  substances  passes  rapidly  doAvnwards 
to  accumulate  as  reserves  in  the  roots.  Later,  these  reserves  ascend 
again  slowly,  to  supply  the  above-ground  portions  of  the  vine  which, 
though  dormant,  still  require  nutrition.  In  spring,  during  the  period 
just  before  and  just  after  the  starting  of  the  buds,  this  upward  migra- 
tion of  reserves  is  more  rapid  and  continues  until  the  young  leaves  are 
sufficiently  developed  to  supply  the  vine  with  its  carbohydrate  food.1 

If  we  prune  a  vine,  therefore,  immediately  after  the  fall  of  the 
leaves,  the  cuttings  contain  the  largest  amount  of  reserves  and  are  in 
the  best  condition  for  use  in  grafting  or  planting.  Three  or  four  weeks 
later,  the  roots  contain  the  largest  amount  of  reserves,  and  if  pruning 
is  done  then,  they  will  be  in  the  best  condition  to  promote  a  vigorous 
growth  in  the  spring.  When  the  buds  start  in  the  spring,  the  root  has 
lost  some  of  its  reserves,  which  have  been  used  up  by  the  canes  during 
the  winter.  Pruning  at  this  time,  therefore,  results  in  a  less  vigorous 
growth  of  shoots,  but  also,  usually,  in  a  better  "setting"  of  the  crop. 

The  effects  of  the  time  of  pruning  on  the  vigor  and  crop  of  the  vine 
have  been  investigated  by  Professor  Ravaz2  in  a  series  of  experiments 
extending  over  seven  years,  with  results  which  have  been  in  the  main 
corroborated  by  tests  at  the  University  Farm. 

Vines  pruned  immediately  after  the  fall  of  the  leaves  were  the 
earliest  to  start  in  the  spring.  Those  pruned  when  the  vines  were  most 
dormant  (end  of  December  and  beginning  of  January)  started,  on  the 
average,  four  days  later.  Those  pruned  at  the  time  pruned  vines 
commence  to  bleed  (about  February  20  in  the  south  of  France)  started 
about  six  days  later.  Pruning  when  the  terminal  buds  commenced  to 
swell  (March)  retarded  the  lower  buds  eleven  days,  and  where  the 
terminal  buds  had  grown  two  or  three  inches,  twenty  days. 

The  starting  of  the  buds  was  late,  therefore,  in  proportion  to  the 
lateness  of  the  pruning.  One  exception,  however,  was  noticed.  Vines 
pruned  soon  after  the  vintage  and  while  still  covered  with  green  leaves 
started,  on  the  average,  ten  days  later  than  those  pruned  after  the  fall 
of  the  leaves. 

The  retardation  of  the  starting  of  the  shoots  in  the  spring  may  be 
a  valuable  means  of  escaping  the  injurious  effects  of  spring  frosts.  In 
one  of  our  tests,  the  crop  on  nine  rows  pruned  March  13  wras  saved, 
while  that  of  twelve  rows  pruned  November  19  and  December  21  was 
completely  ruined  by  a  frost  on  April  21.  Late  pruning  also  retards 

1  Vidal,  J.  L.,  "Les  reserves  de  la  vigne, "  Eevue  de  Viticulture,  I,  895  to 
903. 

2Eavaz,  L.,  "Taille  hative  ou  taille  tardive,"  1912. 


28  UNIVERSITY    OP    CALIFORNIA EXPERIMENT    STATION 

the  blossoming,  though  to  a  less  degree  than  it  does  the  starting.  Prun- 
ing as  late  as  March  may  retard  the  blossoming  ten  days.  The  time 
of  ripening  is  also  influenced  slightly  in  the  same  direction.  When 
spring  frosts  occur,  this  influence  appears  to  be  reversed.  The  vines 
pruned  early  may  blossom  and  ripen  their  fruit  later.  This  is  because, 
the  frost  having  destroyed  the  first  shoots,  the  only  flowers  and  fruit 
that  appear  are  on  buds  which  have  started  after  the  frost. 

Vines  pruned  before  the  fall  of  the  leaves  are  weakened.  Other- 
wise the  time  of  winter  pruning  has  little  direct  effect  on  the  vigor  of 
the  vines.  Professor  Ravaz  notes  somewhat  greater  vigor  in  vines 
pruned  earliest  in  the  dormant  season.  On  these  vines  the  crop  was 
diminished  by  frost.  The  extra  vigor  was  due,  therefore,  probably  not 
to  the  time  of  pruning  but  to  the  lack  of  crop. 

Late  pruned  vines  gave  on  the  average  larger  crops.  Professor 
Ravaz  accounts  for  this  by  their  escape  from  frost.  The  later  blos- 
soming, which  increases  the  probability  of  warm  dry  weather  for 
pollination,  may  also  be  a  factor.  At  the  University  Farm  Muscat 
vines  pruned  in  the  middle  of  April  produced  22.6  pounds  per  vine, 
while  vines  pruned  in  December  produced  only  10.1  pounds,  with  no 
injury  from  frost  in  either  case. 

Pruning  may  be  done,  therefore,  in  frostless  locations  and  with 
varieties  which  set  their  fruit  well  at  any  time  when  the  vines  are 
without  leaves.  Where  spring  frosts  are  common,  the  pruning  should 
be  as  near  the  time  of  the  swelling  of  the  buds  as  possible.  The  bene- 
fits of  late  pruning  without  its  inconveniences  may  be  obtained  by  the 
system  of  "double"  or  ''clean"  pruning  practiced  in  some  regions. 
This  may  be  applied  in  various  ways.  The  simplest  is  to  shear  off  all 
the  canes  to  a  length  of  15  to  18  inches  at  any  convenient  time  during 
the  winter.  This  permits  plowing  and  other  cultural  operations,  and 
the  final  pruning  is  done  in  April.  A  better  method  is  to  prune  the 
vines  as  usual  but  to  leave  the  spurs  with  four  or  five  extra  buds. 
These  spurs  are  then  shortened  back  to  the  proper  length  as  late  as 
practicable.  In  some  cases  the  method  practiced  in  the  Medoc  may  be 
used.  This  consists  in  leaving  a  foot  or  fifteen  inches  of  cane  beyond 
the  last  bud  needed  and  removing  all  the  extra  buds  at  the  time  of 
pruning.  The  starting  of  the  base  buds  is  retarded  by  a  piece  of  cane 
above  them  whether  this  piece  of  cane  has  buds  or  not. 

Early  pruning  (December)  promotes  the  vigor  of  the  vine  and 
results  in  early  starting  of  the  buds.  Late  pruning  (March,  April) 
promotes  fruiting,  may  slightly  weaken  the  vines,  and  results  in  late 
starting  of  the  buds.  Weak  vines,  those  which  have  borne  too  much 
Or  which  have  been  injured  by  insects  or  diseases,  are  better  pruned 


BULLETIN  241-246  yiNE  PRUNING   IN    CALIFORNIA  29 

early.  Very  vigorous  vines,  especially  in  frosty  locations,  should  be 
pruned  late. 

Amount  of  Pruwing. — An  average  vine  before  pruning  may  have 
twenty-five  canes,  with  an  average  of  fifteen  buds  on  each,  or  three 
hundred  and  seventy-five  buds  in  all.  If  the  vine  is  not  pruned,  all 
these  buds  will  not  start  or  produce  shoots.  Probably  not  more  than 
fifty  or  one  hundred  will  do  so.  If  we  prune  the  canes  back  so  that 
we  leave  only  fifty  or  one  hundred  buds,  the  same  number  of  shoots 
will  be  produced.  The  only  effect  will  be  that  buds  nearer  the  bases 
of  the  canes  will  start  instead  of  buds  near  the  ends.  ( See  Physiolog- 
ical Principal  No.  5,  p.  26).  The  quality  and  quantity  of  the  crop  and 
the  vigor  of  the  vine  and  its  shoots  will  be  influenced  little  if  at  all. 

If  we  prune  the  vine  more  severely  and  leave  only  half  this  number 
of  buds,  a  smaller  number  of  shoots  will  be  produced.  As  this  smaller 
number  has  the  same  store  of  reserve  material  in  trunk  and  root  to 
draw  on  and  the  same  root  system  to  supply  water  and  soil  nutrients, 
each  shoot  will  grow  larger  and  more  vigorously.  See  Principle  No.  7, 
p.  26.)  This  smaller  number  of  large  shoots  will  produce  approxi- 
mately as  much  foliage  as  the  larger  number  of  small  shoots  on  the 
unpruned  vine,  and  the  vigor  of  the  vine  is  therefore  not  perceptibly 
diminished. 

There  will  also  be  a  smaller  number  of  bunches  produced,  but  each 
of  these  will  be  larger  and  have  larger  berries,  so  that  the  total  weight 
of  the  crop  will  be  as  large  as  on  an  unpruned  vine.  In  fact,  the 
weight  of  crop  will  probably  be  larger,  as  it  is  easier  for  the  vine  to 
supply  the  water  and  sugar  which  constitute  the  main  bulk  of  large 
berries  than  the  stems,  seeds,  and  skins  which  form  a  larger  part  of 
small  berries. 

"We  can  increase  the  severity  of  the  pruning,  that  is,  dimmish  the 
number  of  buds  left,  still  further,  without  materially  influencing  either 
the  vigor  of  the  vine,  the  amount  of  foliage,  or  the  weight  of  crop. 
Beyond  a  certain  point,  however,  the  crop  is  diminished.  There  are 
two  reasons  for  this.  One  is  that  there  is  a  certain  maximum  size  for 
the  bunches  and  berries  of  any  particular  vine.  When  we  have  reached 
this  maximum,  any  further  decrease  of  fruit  bunches  results  in  a 
diminished  crop.  The  other  is  that  the  excessive  vigor  given  to  the 
shoots  is  unfavorable  to  fruiting  (see  Physiological  Principle  No.  2, 
p.  25),  often  causing  "coulure"  or  dropping  of  the  blossoms  without 
"setting."  The  pruner  should  endeavor,  therefore,  to  leave  just 
enough  fruit  buds  to  furnish  the  number  of  bunches  that  the  vine 
can  bring  to  perfection. 


30  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

Beyond  this  point  the  crop  is  diminished  and  the  vigor  of  the  vine 
correspondingly  increased.  This  increase  of  vigor  is  not  the  direct 
effect  of  the  pruning,  but  of  the  curtailment  of  the  crop,  which  frees 
a  larger  part  of  the  energies  of  the  vine  for  the  work  of  growth  and 
the  building  up  of  tissues  and  reserves.  It  seems  highly  probable  that 
the  direct  effect  of  the  pruning  is  really  weakening,  and  that,  if  the 
only  object  were  growth  and  vigor,  it  could  be  accomplished  better  by 
removing  the  blossoms  in  the  spring  and  doing  no  pruning  in  the 
winter.  The  weakening  effect,  however,  of  even  the  heaviest  pruning 
is  probably  much  less  than  with  most  woody  plants  because  the  vine 
produces  shoots  from  dormant  and  adventitious  buds  with  so  much 
facility,  and  the  amount  of  growth  and  foliage  than  can  be  developed 
by  sterile  shoots  in  a  single  year  is  so  great. 

Heavy  winter  pruning,  therefore,  invigorates  the  vine  by  dimin- 
ishing the  crop.  Light  winter  pruning  increases  the  crop.  If  this 
increase  is  represented  by  a  larger  number  of  bunches  than  the  vine 
can  properly  nourish,  the  crop  will  be  inferior  in  quality  and  the  vine 
weakened  by  over-bearing.  On  a  mature  vine  of  normal  vigor,  the 
pruner  should  leave  the  same  number  of  spurs  and  fruit  buds  as  was 
left  the  year  before.  If  the  vine  appears  abnormally  vigorous,  more 
fruit  buds  should  be  left  in  order  to  utilize  this  vigor  in  the  production 
of  crop.  On  the  other  hand,  if  the  vine  appears  weak,  it  should  be 
pruned  more  severely  than  the  previous  year,  that  is,  fewer  fruit  buds 
should  be  left,  in  order  to  strengthen  the  vine  by  diverting  its  activities 
from  crop  production  to  building  up  tissues  and  replenishing  its  store 
of  reserve  food  materials.  Any  attempt  to  make  a  weak  vine  bear  a 
large  crop  can  result  only  in  further  weakening  of  the  vine  and  in 
the  production  of  inferior  grapes.  By  pruning  such  a  vine  for  a  small 
crop  the  grapes  obtained  will  be  of  good  quality  and  the  vine  invigor- 
ated so  that  it  can  produce  normal  crops  in  subsequent  years. 

These  arguments  apply  not  only  to  individual  vines  but  to  indi- 
vidual arms  or  canes  of  a  vine.  The  number  of  fruit  canes,  spurs,  or 
buds  should  be  in  proportion  to  the  strength  of  the  arm.  A  fruit 
cane  or  fruit  spur  should  be  longer  the  more  vigorous  it  is. 

The  vigor  of  a  vine  is  determined  not  only  by  the  growth  it  has 
made  but  by  the  amount  of  reserves  contained  in  its  canes  and  body. 
Its  condition  in  this  respect  can  be  determined  by  an  inspection  of 
the  canes.  These  should  be  firm  and  heavy.  Soft,  pithy  canes  indicate 
weakness,  and  should  never  be  left  for  fruit  canes.  If  all  or  most  of 
the  canes  on  a  vine  are  of  this  character,  the  vine  should  be  pruned 
very  short ;  in  extreme  cases,  sufficiently  short  to  prevent  any  attempt 
to  bear.  On  the  other  hand,  long,  firm  canes  should  be  made  to  pro- 
duce fruit  by  being  left  longer  whether  as  fruit  spurs  or  fruit  canes. 


BULLETIN   241-246  VINE  PRUNING   IN    CALIFORNIA  31 

The  iodine  test  is  useful  in  determining  the  condition  of  canes  or 
vines  in  respect  to  reserves.  For  this  test  a  solution  of  iodine  in  75 
per  cent  alcohol  is  used,  100  parts  of  alcohol  to  one  part  of  iodine,  by 
weight.  A  clean,  slanting  cut  is  made  through  the  cane  and  a  few 
drops  of  the  solution  placed  on  the  cut.  In  three  to  five  minutes  a 
well  nourished  cane,  containing  abundance  of  starch  (reserves),  turns 
black  all  over  the  cut.  An  imperfectly  nourished  cane  will  turn  black 
only  on  the  medullary  rays,  which  will  show  like  the  spokes  of  a  wheel. 
If  only  a  few  black  specks  are  produced  by  the  iodine,  reserves  are 
lacking.  In  the  first  case  the  canes  are  good  for  use  as  cuttings  or 
grafts  and  indicate  that  the  vine  is  capable  of  producing  a  good  crop. 
The  pruning  should  be  correspondingly  generous.  In  the  last  case 
the  cuttings  are  useless  and  the  vine  should  be  pruned  very  short.  A 
few  tests  of  this  kind  in  a  vineyard  will  give  a  fair  idea  of  the  amount 
of  reserves  in  the  vines,  and  such  a  test  is  a  valuable  aid  in  determining 
the  amount  of  pruning  to  give. 

Young  and  Old  Vines. — During  the  first  part  of  the  life  of  the  vine 
the  main,  if  not  the  only,  object  of  the  pruner  is  to  develop  a  frame- 
work of  proper  form.  The  methods  of  doing  this  and  the  time  re- 
quired will  depend  on  the  form  aimed  at  and  on  the  more  or  less  favor- 
able conditions  for  rapid  growth.  The  crop  during  this  formative 
period  should  be  a  secondary  object.  In  fact,  nothing  is  lost  if  it  is 
left  out  of  consideration  altogether,  except  in  so  far  as  it  affects  the 
attainment  of  the  desired  form.  Vines  which  are  pruned  so  as  to 
reach  most  rapidly  and  perfectly  a  desirable  shape  will  not  only  bear 
more  when  they  reach  adult  size  but  will  practically  always  bear  more 
fruit  during  the  formative  period  than  if  the  fruit  alone  were  in  view. 

In  pruning  an  adult  vine,  two  objects  must  be  kept  in  view :  first, 
the  production  of  the  crop  of  the  current  year,  and  second,  the  mainte- 
nance of  the  proper  form  of  the  vine.  Each  of  these  objects  is  perhaps 
of  equal  importance.  On  the  attainment  of  the  first  depends  the 
current  crop,  on  that  of  the  second  all  future  crops. 

Units  of  Pruning. — "When  a  vine  has  reached  the  stage  of  full 
bearing,  pruning  consists  in  leaving  certain  parts  of  the  new  wood 
for  fruiting,  other  parts  for  renewal  or  the  production  of  wood  for  the 
next  year,  and  finally  other  parts  for  the  replacing  or  shortening  of 
arms.  All  new  wood  not  needed  for  these  purposes  and  all  arms  to 
be  replaced  are  removed. 

Whatever  the  system  of  pruning  adopted,  in  all  our  California!! 
systems  each  arm  of  each  vine  is  treated  by  the  same  method,  modified 
only  by  the  vigor  of  the  individual  cane,  arm,  or  vine.  There  are  two 
general  methods  used,  viz.,  spur  pruning  and  cane  pruning.  The 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


treatment  of  a  single  arm  by  either  of  these  methods  may  be  called 
the  "unit  of  pruning." 

The  unit  of  pruning  in  spur  pruning  is  illustrated  in  Fig.  11, 
representing  a  long  arm  about  seven  years  old.  At  the  end  of  the  arm 
is  shown  the  two-eye  spur  ($2)  of  the  previous  year  bearing  two  canes 
( C  and  Cl ) .  Near  the  base  of  the  arm  is  shown  a  single  water-sprout 
(W$)  growing  out  of  old  wood.  Such  an  arm  would  normally  bear 
other  canes,  but  as  they  would  all  be  removed  entirely  at  pruning  they 
are  omitted  to  simplify  the  figure. 

In  pruning  such  an  arm,  one  of  the  canes  growing  out  of  the  spur 
of  the  previous  year  (82)  is  cut  back  to  form  a  new  spur  and  the  other 
removed  entirely.  In  deciding  on  which  cane  to  use  for  the  new  spur, 


Fig.  11. — Unit  of  short  pruning. 

we  must  choose  one  that  is  suitable  for  fruiting,  viz.,  well  ripened,  of 
moderate  thickness,  and  with  well  formed  buds.  Of  those  which  fulfill 
this  condition,  we  must  choose  that  which  is  in  the  best  position  to 
preserve  the  form  of  the  vine.  This,  in  most  cases,  will  be  the  lowest 
(C  in  the  figure),  because  it  increases  the  length  of  the  arm  the  least. 
If  the  lowest,  however,  is  weak,  broken,  or  otherwise  unsuitable,  we 
are  obliged  to  take  one  higher  up. 

When  a  cane  arising  from  the  base  bud  of  the  spur  of  the  previous 
year  is  chosen  for  the  new  spur,  the  length  of  the  arm  is  lengthened 
imperceptibly.  A  spur  from  the  first  bud  (C)  will  lengthen  it  usually 
little  over  an  inch,  one  from  the  second  bud  (C)  three  or  four  inches. 
In  any  case,  the  arm  finally  becomes  too  long,  like  the  one  in  the  figure. 
It  must  then  be  shortened  or  replaced.  This  can  be  done  by  using  a 
conveniently  placed  water-sprout  for  a  replacing  spur,  as  at  R  in  the 
figure,  and  cutting  back  the  arm  in  the  place  indicated  by  the  line  g. 


BULLETIN  241-246 


VINE   PRUNING    IN    CALIFORNIA 


33 


This  cutting  back  of  an  arm  should  be  deferred  until  the  following 
year,  as  the  replacing  spur  will  produce  little  or  no  fruit.  In  the  mean- 
time the  fruit  spur  from  cane  C  will  bear  a  crop  and  the  replacing 
spur  R  will  produce  fruit  wood  for  the  following  year. 

The  cane  chosen  (C)  is  cut  at  a,  b,  or  d,  leaving  a  fruit  spur  of 
one,  two,  or  three  fruit  buds  and  the  cane,  C\,  removed  entirely  by  a 
cut  at  /.  The  more  vigorous  the  variety  and  the  particular  cane  the 
more  buds  should  be  left.  The  water-sprout  is  cut  back  at  a,  leaving  a 
replacing  spur  of  one  eye.  Of  course,  a  replacing  spur  is  left  only  in 
case  the  arm  is  too  long  and  will  require  shortening  the  next  year. 


Fig.  12. — Unit  of  long  pruning. 

The  unit  in  short  pruning  consists  then  of  a  single  fruit  spur  of 
one,  two,  or  three  fruit  buds. 

The  unit  of  pruning  in  long  and  half  long  systems  is  shown  in 
Fig.  12,  and  consists  of  a  fruit  cane,  F2,  with  its  renewal  spur,  8^ 

In  the  illustration,  S2  represents  the  renewal  spur  of  two  years 
previous.  On  it  was  left  a  fruit  cane,  F2,  which  has  produced  the  crop 
of  the  previous  season,  and  a  renewal  spur,  819  which  has  produced 
fruit  wood  for  the  present  season. 

In  pruning,  the  fruit  cane  F2  is  removed  entirely  at  g.  The  upper 
cane,  C,  of  the  renewal  spur,  $t,  is  used  for  a  new  fruit  cane  and 
shortened  to  about  /  for  half  long  and  to  about  f1  for  long  priming. 
The  lower  cane,  C1,  is  cut  back  at  a  to  form  a  renewal  spur,  S,  which 
will  produce  the  new  wood  for  the  next  winter  pruning. 


34  i     UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

This  is  the  normal  method  of  procedure,  but  various  modifications 
are  often  necessary.  If  the  cane,  C,  is  unsuitable  on  account  of  lack 
of  vigor,  other  canes  such  as  Clt  or  even  B,  D,  near  the  base  of  the  old 
fruit  cane,  may  be  used  for  a  new  fruit  cane.  The  essential  point  is 
that  the  cane  used  for  this  purpose  shall  originate  from  two-year-old 
wood.  In  the  same  way  any  suitably  placed  cane  may  be  used  for  a 
renewal  spur.  Water-sprouts  from  three-year,  four-year,  or  older  wood 
may  also  be  used  (RP).  The  essential  point  in  this  case  is  that  the 
renewal  spur  shall  be  below  the  fruit  cane,  that  is,  nearer  the  trunk. 

Replacing  spurs  for  shortening  the  arms  are  occasionally  needed, 
as  in  spur  pruning,  but  usually  the  same  spur  can  be  used  both  for 
renewal  and  replacing.  The  water-sprout,  RP,  may  be  used  for  this 
purpose,  cutting  it  at  h  or  6,  according  to  its  vigor. 

Slimmer  or  Herbaceous  Pruning. — Summer  pruning,  of  which  there 
are  many  forms,  consists  in  the  removal  of  buds,  shoots,  or  leaves  while 
they  are  green  or  herbaceous,  and  is  done  therefore  while  the  vine  is 
growing  or  active. 

The  effects  of  summer  pruning  are  in  some  respects  very  different 
from  those  of  winter  pruning  and  in  some  quite  the  opposite.  If  we 
remove  a  part  of  a  cane  in  the  winter,  we  do  not  weaken  the  vine  at 
all ;  in  fact,  we  may  strengthen  it  indirectly  by  diminishing  bearing. 
If  we  remove  a  growing  cane  in  the  summer,  on  the  contrary,  we 
weaken  the  vine  because  we  remove  leaves,  which  are  its  principal 
feeding  organs  and  to  which  it  owes  its  vigor.  (See  Principle  No.  1, 
p.  25.) 

This  weakening  effect  is  greatest  in  the  middle  of  summer  when 
the  vine  is  most  active  and  most  in  need  of  the  food  supplied  by  the 
leaves. 

The  removal  of  all  the  leaves  by  defoliating  insects  at  this  time  may 
kill  the  vine.  The  danger  is  not  so  great  early  in  the  spring,  when  we 
can  remove  a  certain  number  of  small  shoots  without  serious  injury. 
In  fact,  vines  struck  by  spring  frosts  are  often  more  vigorous  the  fol- 
lowing year,  because  the  weakness  due  to  removal  of  leaves  is  more 
than  counterbalanced  by  the  strengthening  due  to  lack  of  crop.  It  is 
least  harmful  late  in  the  autumn  after  the  canes  have  matured  and  the 
leaves  have  begun  to  turn  yellow. 

The  removal  of  growing  shoots  or  parts  of  shoots  also  has  an  effect 
similar  to  that  of  winter  pruning,  viz.,  the  concentration  of  the  growth 
of  the  vine  on  the  parts  which  remain.  This  concentrating  effect  and 
the  weakening  effect  occur  in  inverse  ratio  and  vary  according  to  the 
time  and  method  of  operation.  In  early  spring,  at  the  starting  of  the 
shoots,  the  weakening  effect  is  very  slight  and  the  concentrating  effect 


BULLETIN   241-246  yiNE  PRUNING   IN    CALIFORNIA  35 

almost  as  marked  as  that  of  winter  pruning.  In  early  summer,  with 
the  vines  in  full  growth,  the  weakening  effect  may  be  sufficient  to  com- 
pletely neutralize  the  concentrating  effect,  i.e.,  the  removal  of  some 
of  the  shoots  may  so  weaken  the  vine  that  there  will  be  no  increase  of 
growth  in  those  which  are  left.  Still  later,  the  weakening  effect  may 
exceed  the  concentrating  effect,  i.e.,  the  shoots  which  are  left  will  make 
less  growth  than  if  none  had  been  removed. 

Uses  of  Summer  Pruning. — Summer  pruning  has  various  uses,  of 
which  the  principal  are : 

1.  To  direct  the  growth  into  useful  parts  of  the  vine :  disbudding, 
thinning  of  shoots,  and  topping  of  young  vines;  suckering;  water- 
sprouting. 

2.  To  moderate  the  vigor  of  the  vine  and  so  increase  its  bearing : 
pinching,  topping. 

3.  To  increase  the  size  of  fruit  (at  expense  of  sweetness)  :  topping. 

4.  To  increase  the  shade  on  the  fruit:  topping  or  pinching  to  pro- 
mote upright  position  of  shoots  and  growth  of  laterals. 

5.  To  decrease  the  shade  on  the  fruit :  defoliating. 

Three  other  operations  performed  in  the  summer  may  be  considered 
as  forms  of  summer  pruning,  viz. : 

6.  Thinning  of  the  fruit. 

7.  Ringing. 

8.  Removal  of  scion  and  surface  roots. 

Disbudding  is  practiced  on  young  vines  during  the  second  and  third 
years.  It  consists  in  removing  the  buds  from  the  lower  part  of  the 
stem  of  the  vine  in  order  to  concentrate  the  growth  in  the  shoots  above 
and  to  avoid  the  production  of  canes  low  down  where  they  would  have 
to  be  cut  off  later.  The  buds  are  not  removed  until  they  have  grown 
an  inch  or  two.  Many  of  them  are  dormant  or  adventitious  and  the 
attempt  to  remove  them  earlier  would  make  it  necessary  to  go  over  the 
vineyard  too  often.  The  sooner  they  are  removed,  however,  the  better, 
before  they  have  used  up  much  of  the  reserves  of  the  vine  and  when  the 
concentrating  effect  of  their  removal  is  at  its  maximum.  On  younger 
vines  which  have  not  yet  formed  a  stem,  it  consists  in  removing  all  the 
buds  but  one  in  order  to  concentrate  all  the  growth  ino  a  single  shoot, 
from  which  the  following  year  the  stem  will  be  formed. 

Thinning  of  Shoots. — The  purpose  of  this  operation  is  the  same  as 
that  of  disbudding.  It  is  done  after  the  shoots  have  grown  several 
inches  or  more.  It  is  inferior  to  early  disbudding,  as  it  is  more  weak- 
ening to  the  vine  and  the  concentrating  effect  is  correspondingly  less. 
It  is  simpler  than  disbudding,  as  it  necessitates  going  over  the  vine- 
yard only  once.  It  is  used  principally  during  the  second  year  for  vines 


36  UNIVERSITY   OP    CALIFORNIA — EXPERIMENT   STATION 

which  have  been  cut  back  to  two  buds  at  the  end  of  the  first  season's 
growth. 

Topping  the  Young  Vines. — When  by  disbudding  or  thinning  of 
shoots  during  the  second  year  all  the  growth  has  been  concentrated 
into  a  single  shoot  this  shoot  will  grow  with  great  vigor.  When  it  has 
grown  about  twelve  inches  above  the  top  of  the  stake,  that  is,  above  the 
height  at  which  it  is  intended  to  develop  the  head,  it  should  be  topped. 
This  topping  has  the  effect  of  forcing  the  growth  of  laterals.  These 
laterals  may  be  used  at  the  following  winter  pruning  as  fruit  spurs 
and  as  the  commencement  of  permanent  arms.  If  this  topping  is  not 
done,  there  may  be  very  few  buds  on  the  cane  when  mature  at  the 
height  at  which  it  is  desired  to  make  a  head.  It  will,  therefore,  be 
difficult  to  find  buds  in  the  proper  place  for  the  development  of  the 
arms  and  to  produce  the  crop  of  grapes  which  the  vine  should  yield  the 
third  year. 

During  the  third  summer  the  number  of  shoots  will  be  small  for 
the  vigor  of  the  young  vine.  They  will  grow  rapidly  and  be  very 
liable  to  be  broken  off  by  the  wind  while  tender  and  succulent.  If 
topped  before  they  are  long  enough  to  afford  sufficient  leverage  to  the 
force  of  the  wind,  they  will  have  time  to  lignify  their  tissues  and  be- 
come tough  enough  to  withstand  the  pressure  of  the  wind.  Topping 
at  this  time  helps  to  keep  the  shoots  upright  and  makes  it  easier  to 
give  the  arms  the  proper  direction  at  the  following  winter  pruning. 

Suckering. — This  is  the  removal  of  all  shoots  which  originate  at  or 
below  the  surface  of  the  ground.  Neglect  of  suckering  results  in 
diminished  vigor  of  the  whole  above-ground  portion  of  the  vine.  The 
suckers  bear  little  or  no  fruit,  hence  grow  vigorously  and  appropriate 
the  sap  'which  should  nourish  the  whole  vine.  Finally,  the  top  may 
die,  the  whole  growth  go  into  the  suckers,  and  all  the  benefits  of  a 
properly  shaped  vine  will  be  lost.  Such  a  vine  can  be  renovated  only 
by  cutting  off  the  old  stump  and  building  up  a  new  vine  from  a  vigor- 
ous sucker. 

With  grafted  vines  the  consequences  are  even  more  serious.  The 
suckers,  coming  from  the  stock,  take  the  sap  even  more  easily  from 
the  top,  since  the  top  is  connected  to  the  root  by  the  grafting  union, 
and  the  passage  of  water  and  food  materials  to  the  top  is  therefore 
impeded.  A  grafted  vine  which  has  been  seriously  weakened  by  the 
prolonged  growth  of  suckers  is  useless  and  can  not  be  renovated. 

Suckering  should  be  done  with  the  greatest  care  and  thoroughness 
during  the  first  four  or  five  years.  This  will  save  a  great  deal  of 
expensive  and  troublesome  work  later.  Very  few  suckers  will  be  pro- 
duced by  vines  which  have  been  properly  cared  for  in  this  respect 


BULLETIN  241-246  yiNE  PRUNING  IN   CALIFORNIA  37 

during  the  first  three  years,  and  such  vines  will  usually  cease  to  produce 
any  after  five  or  six  years.  Vines  on  which  the  suckering  has  been 
imperfectly  done  during  the  first  three  years,  on  the  contrary,  will 
always  produce  an  abundant  crop  of  underground  shoots  every  year. 

Suckering,  like  disbudding,  should  be  done  as  early  in  the  season 
as  possible  for  the  reasons  already  given.  Another  and  even  more 
important  reason  is  that  suckers  which  are  removed  late,  and  especially 
those  which  are  allowed  to  grow  the  whole  summer,  promote  the  for- 
mation of  dormant  buds  and  of  tissue  which  readily  forms  adventitious 
buds  below  ground. 

It  is  necessary  to  sucker  young  vines  two  or  three  times  during  the 
spring.  This  is  done  every  time  the  vines  are  visited  for  hoeing  or 
tying  up.  When  the  suckers  are  soft  and  succulent  they  are  easily 
pulled  off  without  cutting.  They  must  be  removed  completely  from 
the  base.  When  they  get  a  little  tough  it  is  necessary  to  dig  down 
to  their  point  of  origin  for  this  purpose.  It  is  worse  than  useless  to 
remove  a  sucker  partially.  The  part  which  remains  forms  an  under- 
ground spur  or  arm  which  will  be  a  source  of  perennial  trouble. 

Water-Sprmiting. — This  is  the  removal  of  sterile  shoots.  When  it 
is  done  to  prevent  growth  in  places  where  growth  is  not  wanted,  or  to 
concentrate  growth  in  parts  where  it  is  wanted,  it  is  advisable.  The 
removal  of  all  sterile  shoots  in  all  cases,  on  the  theory  that  they  are 
useless,  however,  is  mistaken  practice. 

The  growth  of  a  large  number  of  water-sprouts  is  usually  a  sign 
that  the  full  vigor  if  the  vine  is  not  being  used  for  the  production  of 
crop.  The  cure  for  this  is  longer,  or  a  different  style,  of  winter  prun- 
ing. The  production  of  sterile  shoots  on  what  ought  to  be  fruit  wood 
often  indicates  some  cultural  error,  such  as  excess  of  water,  nitrogen 
or  humus,  too  late  growth  of  the  vine  in  autumn,  or  excessive  vigor. 

Water-sprouts  may  be  removed  with  good  results  in  certain  cases. 
If  the  vines  are  weak,  the  growth  may  by  this  means  be  concentrated 
in  the  bearing  shoots,  which  will  thus  be  able  to  nourish  their  crop 
better.  In  this  case  the  water-sprouts  must  be  removed  early,  before 
they  have  grown  more  than  a  few  inches.  Otherwise  the  vine  will  be 
still  further  weakened  and  the  trouble  increased  the  following  year. 
If  the  vines  are  excessively  vigorous,  diminishing  the  foliage  by  the 
late  removal  of  water-sprouts  may  correct  this  defect.  It  is  more 
reasonable,  however,  to  utilize  this  vigor  for  crop  production  by  a 
change  in  the  winter  pruning.  Water-sprouts  are  sometimes  trouble^ 
some  by  growing  through  the  bunches,  making  it  impossible  to  gather 
the  crop  without  injury.  This  is  particularly  harmful  with  shipping 
grapes.  Where  much  of  this  trouble  exists  it  indicates  that  the  vine 


38  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

has  an  unsuitable  shape.  This  can  be  modified  in  the  winter  pruning 
by  spreading  the  vine  sufficiently  to  allow  all  the  bunches  to  hang  free. 

Sterile  shoots  are  by  no  means  completely  useless.  The  foliage 
they  produce  nourishes  the  vine  and  makes  it  more  capable  of  bearing 
fruit.  They  are  needed  for  use  as  renewal  and  replacing  spurs,  for 
which  purpose  they  are  better  than  fruitful  shoots,  since  they  are  more 
vigorous. 

Pinching. — This  consists  of  the  removal  of  the  growing  tip  of  a 
shoot  with  thumb  and  finger.  Its  weakening  effect  is  very  slight,  as 
no  expanded  leaves  and  a  very  small  amount  of  material  are  sacrificed. 

Its  immediate  effect  is  to  arrest  the  elongation  of  the  shoot.  If 
this  is  done  when  the  shoot  is  15  to  18  inches  long,  the  shoot  has  time 
to  become  sufficiently  tough  to  resist  the  wind  before  it  gets  long 
enough  to  afford  the  wind  much  pressure  surface.  Shoots  pinched  as 
early  as  this  usually  produce  a  new  growing  tip  from  a  lateral  which 
later  can  not  be  distinguished  from  an  original  growing  tip.  Later 
pinching  usually  causes  the  growth  of  several  strong  laterals. 

Pinching  fruit  shoots,  just  before  blossoming,  tends  to  make  the 
fruit  "set"  better.  It  is,  therefore,  a  remedy  for  "coulure."  Pinch- 
ing the  first  shoots  on  a  fruit  cane  tends  to  promote  the  starting  of  other 
buds,  and  therefore  the  production  of  more  bunches.  By  pinching 
we  can  accomplish  most  of  the  objects  of  topping  with  a  minimum 
weakening  effect  on  the  vine.  Fig.  9  shows  a  fruiting  shoot  at  the 
proper  stage  for  the  first  pinching. 

Topping  Bearing  Vines. — This  consists  in  removing  one,  two,  or 
more  feet  of  the  end  of  a  growing  shoot,  usually  in  June  or  July  or 
later.  In  some  regions  topping  is  practiced  regularly  twice  or  even 
three  times  during  the  season.  In  general,  it  is  used  more  in  the  cooler 
districts  than  in  the  hotter. 

If  practiced  early,  it  has  much  the  same  effect  as  pinching.  It 
tends  to  keep  the  canes  upright  and  to  cause  the  development  of  lat- 
erals. It  involves  the  removal  of  leaves  and  is  therefore  weakening, 
which  may  be  an  advantage  with  extra  vigorous  vines.  In  very  windy 
districts  it  is  necessary  to  prevent  the  shoots  from  being  broken  off 
by  the  wind.  The  later  the  topping  is  done  the  more  leaves  are  re- 
moved and  the  more  weakening  the  practice  is  to  the  vine.  Constant 
severe  topping  may  have  a  serious  effect  on  the  vigor  of  even  the 
strongest  vines.  Topping  nearly  always  decreases  the  crop.  Topping 
three  times  at  Davis  diminished  the  crop  of  Tokays  by  32  per  cent  and 
of  Carignanes  by  42  per  cent. 

In  general,  moderate  topping  tends  to  increase  the  size  of  the  grapes 
and  to  decrease  their  quality.  For  table  grapes  on  vigorous  vines  it 


BULLETIN   241-246  VINE  PRUNING   IN    CALIFORNIA     •  39 

is  sometimes  an  advantage  if  not  carried  too  far.  At  least  three  or 
four  leaves  should  be  left  above  the  fruit  when  the  topping  is  done 
early  and  seven  or  eight  when  the  topping  is  done  late.  For  wine  or 
raisin  grapes  it  is  seldom  advisable,  as  it  decreases  the  sugar  and  flavor 
of  the  grapes.  "With  long  pruned  vines,  especially  when  trellised,  it 
is  often  possible  to  obtain  the  benefits  of  the  practice  without  its  de- 
fects by  topping  only  the  shoots  on  the  fruit  canes  and  allowing  the 
shoots  on  the  replacing  spurs  to  grow  normally. 

Both  pinching  and  topping  are  used  frequently  with  the  object  of 
protecting  the  fruit  from  sunburn,  by  increasing  the  shade  for  the 
grapes.  For  this  purpose  pinching  is  much  superior  to  topping. 

When  a  shoot  is  allowed  to  grow  without  interference  it  takes  at 
first  a  more  or  less  upright  direction.  As  it  increases  in  length  its 
weight  tends  to  bend  it  over  to  a  more  or  less  horizontal  or  downward 
direction.  With  some  rapidly  elongating  varieties,  the  shoots  bend  over 
and  take  a  reclining  position,  resting  for  a  considerable  portion  of 
their  length  on  the  soil.  With  nearly  all  varieties  they  will  finally 
bend  outward  and  downward  sufficiently  to  open  up  the  center  of  the 
vine  to  the  sun. 

In  many  cases  this  opening  up  of  the  center  is  an  advantage,  pro- 
moting the  coloring  of  the  grapes  and  making  easier  the  control  of 
mildew.  In  some  it  encourages  sunburn  of  the  grapes.  Sunburn, 
however,  is  not  due  alone  to  the  direct  rays  of  the  sun,  since  some 
bunches  completley  exposed  do  not  sunburn  and  others  much  shaded 
do.  Sunburn  occurs  in  vineyards  where  the  shade  temperature  seldom 
goes  above  100°  F.  and  may  not  occur  in  others  where  it  often  rises 
to  110°  F. 

The  commonest  form  of  sunburn  is  due  to  an  excess  of  evaporation 
over  sap  supply.  If  more  water  is  lost  through  the  skin  of  the  grape 
than  is  supplied  through  the  stem,  it  will  dry  up.  An  excess  or  a 
deficiency  of  water  in  the  soil  may  curtail  the  sap  supply  and  sunburn 
will  result.  Defective  or  diseased  roots,  wounds,  or  fungi  in  stems 
or  arms  may  have  the  same  effect.  Increasing  the  shade,  therefore, 
is  merely  a  palliative,  and  any  method  which  weakens  the  vine  will 
increase  the  trouble. 

If  we  pinch  the  growing  shoots  once  or  twice  before  they  are  three 
feet  long,  we  increase  the  shade  in  two  ways.  First,  they  grow  more 
upright  as  they  are  relieved  from  the  weight  of  the  growing  top  until 
they  are  sufficiently  lignified  to  retain  their  upright  position.  Second, 
they  produce  laterals  which  increase  the  number  of  leaves  near  their 
bases  and  over  the  head  of  the  vine.  Topping,  being  done  later,  is  less 
effective  in  these  respects,  and,  moreover,  as  it  involves  the  removal 


40  UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 

of  feeding  leaves  may  weaken  the  vine  so  much  as  to  increase  the 
trouble. 

Defoliating. — The  development  of  the  color  of  the  grapes  is  influ- 
enced more  by  the  light  than  by  the  heat  of  the  sun.  The  coloring  of 
Tokay  grapes  can  sometimes  be  facilitated  in  the  cooler  districts  by 
means  which  expose  the  bunches  to  more  sunlight.  One  of  these  means 
is  the  removal  of  leaves.  This,  of  course,  will  tend  to  weaken  the  vine. 
If  the  vines  are  excessively  vigorous,  this  may  not  be  a  disadvantage. 
If  only  the  leaves  in  the  center  of  the  vine,  which  have  already  com- 
menced to  turn  yellow,  are  removed,  the  weakening  effect  may  be  very 
slight.  Better  insolation,  however,  can  usually  be  obtained  more 
profitably  by  changing  the  form  of  the  vine  or  by  thinning  the  bunches. 

Removal  of  the  interior  leaves  may  be  useful  in  some  cases,  with 
very  late  varieties,  to  protect  them  from  molding  after  rains.  It  allows 
sun  and  air  to  reach  the  grapes  freely  and  helps  the  moisture  to  evap- 
orate quickly  from  their  surfaces. 

"Sheeping"  the  vineyard,  or  allowing  sheep  to  eat  the  leaves  im- 
mediately or  soon  after  gathering  the  crop,  is  undoubtedly  a  bad 
practice.  It  removes  the  leaves  before  they  have  fulfilled  their  im- 
portant duty  of  providing  the  reserve  food  to  be  stored  up  in  cane, 
trunk,  and  roots  for  the  growth  of  the  following  spring. 

Thinning  the  Fruit. — Many  otherwise  suitable  grapes  do  not  ship 
well  on  account  of  the  excessive  compactness  of  the  bunch.  A  compact 
bunch  is  difficult  to  pack  without  injury  and  can  not  be  freed  from 
imperfect  berries  without  spoiling  good  berries. 

This  excessive  compactness  can  be  prevented  by  thinning  before 
the  berries  are  one-third  grown.  Thinning,  moreover,  increases  the 
size  of  the  berries,  hastens  ripening,  promotes  coloring,  and  lessens 
some  forms  of  sunburn.  The  practice  is  regularly  followed  with  suc- 
cess by  many  growers  of  Tokay,  Black  Morocco,  Luglienga,  and  other 
grapes,  whose  bunches  are  usually  too  compact.  While  apparently 
costly,  the  expense  is  often  more  than  counterbalanced  by  the  saving 
in  trimming  of  the  ripe  grapes.  The  increase  of  quality  thus  becomes 
a  net  gain. 

The  bunches  are  thinned  at  any  time  after  the  berries  have  set  and 
before  they  have  reached  one-third  their  mature  diameter.  No  bunches 
are  removed,  only  a  certain  proportion  of  the  berries  of  each  bunch. 
The  number  of  berries  to  be  removed  will  depend  upon  how  compact 
the  unthinned  bunches  usually  become.  In  general,  it  will  vary  from 
one-third  to  one-half  of  the  total  number.  The  thinning  is  effected  by 
cutting  out  several  of  the  side  branchlets  of  the  bunch.  The  branch- 
lets  should  be  removed  principally  from  the  part  of  the  bunch  which 


BULLETIN   241-246  VINE  PRUNING   IN    CALIFORNIA 


41 


A  B 

Fig.  13. — Bunch  of  green  grapes  before  (A)  and  after  (B)  thinning. 


42 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


has  most  tendency  to  compactness,  usually  the  upper  part.  The  work 
can  be  done  very  rapidly,  as  no  great  care  is  necessary  in  preserving 
the  shape  of  the  bunch.  However  irregular  or  one-sided  the  bunch 


Fig.  14. — Black  Morocco  improved  by  thinning. 

looks  immediately  after  thinning,  it  will  round  out  and  become  regular 
before  ripening. 

A  long,  narrow-bladed  knife  or  a  pair  of  grape-trimming  scissors 
can  be  used  conveniently  for  this  work. 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


43 


Ringing. — This  operation,  called  also  "cincturing"  and  "annular 
incision,"  consists  in  the  removal  of  a  ring  of  bark  from  a  growing 
shoot,  a  cane,  an  arm,  or  the  trunk.  It  is  performed  by  means  of  a 
special  two-bladed  knife  (see  Fig.  15)  or  other  instrument,  according 
to  the  size  of  the  part  of  the  vine  to  be  treated.  The  ring  is  removed 
from  a  part  of  the  vine  below  the  fruit.  This  prevents  the  passage  of 
food  material  to  the  lower  parts  of  the  vine  and  causes  its  accumu- 
lation in  the  parts  above  the  incision. 


8 


Fig.  15. — Cincturing  knife. 

The  knife  should  not  penetrate  the  wood  and  the  ring  of  bark 
removed  should  be  from  one-third  to  one-fourth  of  an  inch  in  width. 
If  it  is  too  narrow,  the  wound  heals  too  quickly  and  the  full  effect  of 
the  operation  is  not  obtained ;  if  too  wide,  the  part  treated  may  die. 

Ringing  is  used  to  (1)  increase  the  size  of  the  fruit  and  to  hasten 
the  ripening;  (2)  to  prevent  "early  coulure,"  the  dropping  of  the 
blossoms  without  "setting";  (3)  prevent  "late  coulure,"  the  dropping 
of  the  small,  immature  berries  after  setting. 

For  the  first  purpose  the  ringing  is  practiced  on  the  cane  just  below 
the  fruit  or  on  the  arm.  It  is  done  after  the  berries  have  set  and 
reached  about  one-third  full  size.  For  the  second  purpose  it  is  done 
a  few  days  before  the  blossoms  open,  and  for  the  third  a  few  days  after 
the  berries  have  set. 

All  forms  of  ringing  are  more  or  less  weakening  to  the  vine,  and 
it  is  seldom  possible  to  treat  the  same  vine  in  this  way  for  several  years 


44  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

in  succession  without  serious  injury.  An  exception  to  this  is  the  ring- 
ing oMhe  Black  Corinth  in  Greece  and  Australia,  which  has  been  prac- 
ticed for  years  and  has  lately  been  tried  with  success  in  California. 
In  this  case  the  ringing  is  done  to  the  main  trunk  at  or  near  the  sur- 
face of  the  ground  and  the  wound  is  covered  with  soil  immediately. 
This  practice  produces  large  and  regular  crops  on  a  variety  which 
usually  bears  hardly  any  crop  without  it. 

Ringing  the  trunk  in  this  way  has  proved  much  less  dangerous  than 
what  at  first  sight  would  seem  to  be  a  milder  operation,  the  ringing 
of  single  arms.  The  reason  is,  probably,  that  when  the  wound  is  pro- 
tected by  a  covering  of  soil  it  heals  perfectly,  but  when  exposed  as  it 
is  on  an  arm  it  fails  to  heal  or  heals  only  in  part. 

Removal  of  Surface  Roots. — As  has  already  been  pointed  out,  the 
final  position  of  the  feeding  roots  depends  on  the  soil  conditions  and 
can  not  be  influenced  by  pruning.  The  position  of  the  main  roots  can, 
however,  be  modified  to  some  extent  in  certain  cases. 

Young  vines  in  some  soils  tend  to  start  roots  at  or  very  close  to  the 
surface  of  the  ground.  This  is  especially  frequent  where  summer 
irrigation  is  practiced.  If  these  roots  are  allowed  to  grow,  they  will 
form  main  roots  and  are  liable  to  injury  in  cultivation.  During  the 
first  and  second  year,  therefore,  it  is  advisable  to  cut  off  any  roots  which 
form  within  four  or  five  inches  of  the  surface.  This  can  be  done  when 
the  vines  are  hoed  and  suckered.  When  grafted  vines  are  planted,  the 
union  is  placed  above  the  ground  but  is  covered  by  "hilling"  up  the 
soil.  This  may  cause  roots  to  start  from  the  scion.  These  roots  must 
be  carefully  cut  off  before  they  become  large  or  the  vine  will  fail  to 
nourish  its  resistant  roots. 

Restriction  and  Treatment  of  Wounds. — The  possible  length  of  life 
of  a  vine  so  far  as  we  know  is  unlimited.  The  actual  profitable  life 
varies  from  a  few  years  to  fifty  or  more.  Vines  are  sometimes  killed 
by  some  disease  or  unfavorable  conditons,  such  as  severe  frosts,  pro- 
longed drought,  etc.  Most  vines  fail  and  become  unprofitable  from 
the  effects  of  an  accumulation  of  small  injuries.  Among  the  chief  of 
these  are  pruning  wounds.  Wounds  are  not  only  harmful  in  them- 
selves by  destroying  wood,  bark,  and  other  conducting  tissues,  but  they 
allow  the  entrance  of  boring  insects  and  wood-destroying  fungi  whose 
effects  are  even  more  destructive. 

All  pruning  wounds,  therefore,  should  be  made  as  small  as  possible, 
especially  in  the  main  body  and  other  permanent  parts  of  the  vine. 
The  necessity  of  making  large  wounds  can  be  avoided  to  a  great  extent 
by  using  foresight. 


BULLETIN   241-246  VINE  PRUNING   IN    CALIFORNIA 


45 


\ 


Fig.  16. — Spore-bearing  bodies  of  an  "oyster-shell  fungus"  showing  fungous 
decay  of  the  trunk  due  to  large  pruning  wounds. 


46 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


Useless  shoots  and  canes  should  be  removed  while  they  are  small 
and  young,  and  necessary  renewals  of  arms  or  branches  should  be 
made  before  the  part  to  be  suppressed  becomes  too  large.  Where  large 
wounds  are  unavoidable,  they  should  be  made  as  smooth  as  possible 
and  protected  by  an  antiseptic  swabbing  with  2  per  cent  copper  sulfate 
solution  and  covered  with  a  good  white  lead  paint.  The  vine  heals  its 
wounds  from  the  inside  by  the  production  of  gummy  matters  or  thy- 
loses  which  fill  up  the  cells  and  tissues  and  so  prevent  loss  of  sap.  It 


Fig.  17. — Proper  position  of  pruning  shears  with  relation  to  the  vine  when 
making  a  cut. 

does  not  cover  the  wounds  with  healing  tissue  from  the  outside  with  the 
facility  that  many  fruit  trees  possess.  Wounds  much  over  an  inch  in 
diameter  seldom  heal  over  completely. 

By  careful  and  skillful  use  of  the  pruning  tools  the  harm  of  neces- 
sary wounds  can  be  reduced  to  a  minimum. 

All  cuts  should  be  made  clean  and  smooth.  This  requires  that  the 
shears  should  be  of  good  quality  and  kept  sharp.  The  cuts  should  be 
made  in  such  a  way  that  there  is  no  splitting  or  cracking  of  the  wood. 
This  is  accomplished  by  holding  the  shears  in  the  proper  way  at  the 
proper  angle  and  by  avoiding  any  undue  bending  of  the  portion  of  the 
vine  to  be  removed.  Canes  for  spurs  should  be  cut  at  a  slight  angle, 
and  not  at  a  right  angle  to  the  grain.  In  cutting  off  a  cane  or  spur 


BULLETIN  241-246  VINE  PRUNING   IN   CALIFORNIA  4:1 

entirely  the  blade  of  the  shear  should  be  placed  against  the  vine  and 
should  cut  upwards  as  shown  in  Fig.  17.  This  will  insure  a  clean, 
close  cut  without  splitting.  Any  cut  on  the  body  of  the  vine  should 
be  made  in  such  a  way  as  to  leave  as  small  a  wound  as  possible  and  at 
the  same  time  to  leave  no  projecting  stub.  Stubs  of  dead  wood  prevent 
healing  over  and  interfere  considerably  with  future  pruning. 

In  spur  pruning  it  is  considered  best  to  cut  through  the  bud  above 
the  last  one  that  it  is  desired  to  have  grow  as  at  C  in  Fig.  18.  This 
leaves  the  woody  diaphragm  intact  and  protects  the  spur  from  injury. 
If  the  spur  is  cut  at  C1}  a  long  piece  of  internode  is  left  exposing  the 
pith.  As  this  pith  dries  and  shrinks  it  allows  water  to  enter  and  forms 
an  excellent  place  for  molds  to  grow  which  may  destroy  the  bud  below. 
It  requires  some  skill  and  practice  to  cut  exactly  in  the  right  place ; 
if  by  mistake  the  cut  is  made  just  below  the  diaphragm,  the  breeding 
place  for  molds  has  its  maximum  size.  For  this  reason  most  pruners 
make  the  cut  at  C2,  about  half  an  inch  above  the  last  bud.  If  the 
shears  are  sharp  and  the  cut  made  at  an  angle  of  about  45  degrees 
behind  the  bud,  no  injury  results. 

In  removing  a  piece  of  old  wood  at  the  base  of  a  spur  or  fruit  cane 
it  is  best  to  leave  a  little  projecting  stub.  Too  close  cutting  in  this 
case  is  apt  to  injure  the  spur  or  cane.  The  projecting  stub  can  be 
removed  the  following  year,  when  the  spur  has  grown  larger,  without 
danger  of  injury.  (See  Fig.  18.) 

Supports. — With  most  systems  of  pruning,  after  the  vine  has 
reached  a  certain  stage  of  development  and  its  framework  is  complete, 
it  will  support  itself  after  the  manner  of  a  small  tree.  Where  the 
trunk  is  elongated,  as  in  the  Cordon  systems,  the  trunk  requires  a 
permanent  support. 

Young  vines  in  all  systems  require  support  for  at  least  three  or 
four  years,  and  usually  longer.  A  skillful  pruner  can  build  up  a  low 
vine  without  a  support,  but  the  results  are  imperfect  at  best  and  the 
method  requires  so  much  skill  and  care  that  there  is  no  economic  gain. 

In  long  or  cane  pruning  there  must  always  be  some  support  fur- 
nished for  the  fruit  canes. 

The  supports  needed  then  are  of  two  kinds:  (1)  temporary  sup- 
ports to  keep  young  vines  in  place  until  their  trunks  become  large  and 
strong  enough  to  support  themselves,  and  (2)  permanent  supports  for 
long  trunks  or  for  the  annual  fruit  canes. 

Staking. — As  temporary  supports  some  form  of  stake  is  always 
used.  Nearly  all  vine  stakes  in  California  are  made  of  redwood,  which 
is  remarkably  adapted  to  the  purpose.  It  is  light,  easy  to  work,  and 
very  resistant  to  decay  unless  made  from  sap  wood.  Split  stakes  are 


48  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION 

the  best,  as  sawn  stakes  may  be  cut  diagonally  across  the  grain  and 
many  may  break  in  driving. 

Pine,  spruce,  poplar,  willow,  or  any  other  wood  may  be  used  for 
temporary  stakes  if  redwood  is  unavailable.  Most  of  these  woods  will 
last  two  years,  and  can  be  made  to  last  four  or  five  if  treated  with 


Fig.  18. — Methods  of  cutting  the  end  of  a  spur. 

copper  sulfate.  Saplings  and  small  branches  can  sometimes  be  con- 
veniently used.  These  should  be  peeled  and  pointed  as  soon  as  cut 
and  then  stood  for  twenty-four  hours  in  a  tub  containing  a  few  inches 
of  a  5  per  cent  solution  of  copper  sulfate  (bluestone).  At  the  end  of 
this  time  the  copper  sulfate  will  have  penetrated  the  whole  stake  and 
can  usually  be  seen  at  the  upper  end.  If  the  saplings  are  allowed  to 
dry  even  for  a  few  days,  it  will  require  a  very  much  longer  time  to 
impregnate  them  with  the  antiseptic. 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


49 


Other  materials  may  sometimes  be  conveniently  used  for  temporary 
stakes.  The  commonest  of  these  is  the  Spanish  reed  or  bamboo,  Arundo 
donax,  used  in  many  places  as  a  windbreak.  These  are  somewhat 
slender  for  the  purpose  and  require  much  readjusting,  but  will  serve 
when  better  materials  are  not  available. 

The  length  of  the  stake  depends  principally  on  the  height  at  which 
it  is  desired  to  head  the  vine  and  on  the  character  of  the  soil.  It  should 
be  of  such  length  that,  after  being  driven  into  the  ground,  sufficient 
will  be  below  the  surface  to  keep  it  firm  and  prevent  its  being  loosened 
by  the  force  of  the  wind  acting  on  the  vine  tied  to  it,  and  sufficient  will 
be  above  the  surface  to  extend  for  two  inches  above  the  height  at  which 


Fig.  19. — Pruning  tools:   one-hand  shears;  two-hand  shears;  curved  saw. 

it  is  intended  to  head  the  vines.  Its  thickness  should  be  in  proportion 
to  its  height. 

When  redwood  is  used  a  stake  thirty  inches  long  and  one  and  one- 
fourth  inches  square  will  be  sufficient  in  firm  ground  for  small  growing 
vines  like  the  Zinfandel.  This  will  allow  fifteen  inches  to  be  driven 
into  the  ground  and  leave  fifteen  inches  above,  which  is  sufficient  for 
vines  to  be  headed  at  twelve  inches.  If  the  ground  is  loose  or  sandy, 
a  slightly  longer  stake  is  advisable.  For  strong  growing  varieties  such 
as  Carignane  or  Tokay,  especially  when  growing  in  rich  soil,  a  stake 
two  inches  square  and  thirty-six  to  forty-eight  inches  long  is  necessary. 
This  will  permit  the  heading  of  the  vine  at  eighteen  to  thirty  inches. 

When  a  stake  is  used  as  a  permanent  support  for  fruit  canes  it  is 
usually  made  six  feet  long  and  two  or  two  and  one-quarter  inches  in 
diameter.  A  somewhat  shorter  stake,  four  to  five  feet,  will  suffice  if 
the  canes  are  bowed.  A  similar  stake  is  needed  for  a  vertical  cordon. 


50  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

Trellising. — A  trellis  consists  of  one,  two,  or  rarely  three  wires 
stretched  horizontally  along  the  rows.  The  wires  are  held  at  the  ends 
by  heavy  stakes  or  fence  posts  braced  firmly.  These  wires  are  sup- 
ported at  intervals  along  the  row  by  stakes  of  appropriate  height.  A 
tall  stake  at  each  vine  is  often  used  for  this  purpose,  as  it  serves  also 
for  tying  up  the  yearly  replacing  shoots.  This  stake,  however,  is  ex- 
pensive and  troublesome  in  pruning,  and  is  not  indispensable.  It  is 
usually  sufficient  to  place  stakes  at  intervals  of  two  or  even  three  vines. 
Such  stakes  should  be  placed  between  the  vines  and  need  be  long 
enough  only  to  reach  to  the  top  wire.  Some  growers  dispense  with 
these  intermediate  stakes  altogether.  A  temporary  stake  is  used  with 
each  vine  until  it  has  developed  a  self-supporting  trunk.  The  single 
wire  used  is  then  allowed  to  rest  on  the  head  of  each  vine.  If  the  vines 
are  even  and  well  formed,  this  is  a  convenient  arrangement,  as  it  facili- 
tates the  tightening  of  loose  wires  and  the  repair  of  those  which  break. 

The  height  of  the  first  or  only  wire  is  usually  about  thirty  inches, 
that  of  the  second  forty-five  inches,  and  that  of  the  third  fifty-seven 
inches  when  three  are  used.  In  many  cases  one  wire  is  sufficient  to 
support  the  fruit  canes.  In  windy  locations  the  second  wire  is  useful 
to  support  the  growing  shoots.  "With  very  vigorous  vines  the  second 
wire  may  be  used  also  for  fruit  canes.  A  third  wire  may  be  used  in  this 
case  to  support  the  fruit  shoots,  but  is  seldom  or  never  really  needed, 
and  adds  much  to  the  cost  of  both  installation  and  maintenance.  The 
wire  most  used  is  No.  12  galvanized  fencing  wire.  No.  10  or  No.  11  is 
a  little  better,  as  No.  12  will  frequently  break.  When  more  than  one 
wire  is  used  No.  11  for  the  bottom  wire,  which  supports  the  weight  of 
the  fruit,  and  No.  13  for  the  others  is  satisfactory. 

For  the  horizontal  cordon  system  the  same  method  of  trellising  is 
used. 

For  attaching  the  vines,  canes,  and  shoots  to  stakes  and  trellises 
some  form  of  rope  or  string  is  commonly  used.  The  balls  of  twine 
used  on  self-binders  are  convenient  and  preferred  by  some.  This 
twine,  however,  is  not  quite  strong  enough  for  the  main  body  of  the 
vine,  especially  in  windy  locations,  unless  doubled,  though  it  is  ex- 
cellent for  tying  fruit  canes  to  stake  or  trellis.  A  similar  but  heavier 
material  called  grape-twine  is  excellent.  Old  ropes,  such  as  discarded 
ship  cables,  can  sometimes  be  obtained  cheaply,  and,  if  cut  into  suit- 
able lengths,  the  single  strands  are  easily  separated  and  form  very  good 
tying  material. 

It  is  false  economy  to  use  material  for  tying  of  insufficient  strength 
or  durability.  It  results 'in  much  troublesome  extra  work  in  retying 
or  in  defective  vines. 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


51 


In  the  hands  of  very  careful  workmen,  nothing  is  better  than  wire 
for  tying  up  young  vines  at  the  winter  pruning.  It  holds  the  vine 
permanently  and  securely.  Used  carelessly,  however,  it  may  cut  the 
bark,  and  unless  discretion  is  used  in  the  placing  of  the  tie  and  care  in 
its  removal  when  necessary  the  vines  may  be  girdled  and  killed.  The 
wire  from  hay  bales  is  suitable  for  this  purpose,  though  it  is  unneces- 
sarily heavy.  No.  16  galvanized  fencing  wire  is  of  about  the  right 
weight. 

Other  materials  used  are  raffia  for  the  fruit  canes  and  osier  willows 
for  the  body  of  the  vine.  Raffia  is  unreliable  in  strength  and  inferior 
for  this  purpose  to  binding  twine.  Nothing  is  better  than  osier  willow 
to  attach  the  trunk  of  a  young  vine  to  the  stake,  but  it  is  rarely  obtain- 
able and  requires  some  special  skill  to  use. 


Fig.  20. — Burning  the  brush  in  the  vineyard  after  pruning. 

Pruning  Tools. — The  best  tool  for  pruning  vines  is  a  pair  of  shears 
of  the  Swiss  form  (see  Fig.  19).  If  vines  are  properly  pruned  every 
year,  it  will  seldom  be  necessary  to  make  cuts  too  large  for  these  shears, 
except  when  arms  have  to  be  replaced  or  last  year's  fruit  canes 
removed.  For  this  purpose  a  curved  saw  should  be  carried  by  the 
pruner.  For  vines  which  make  a  very  heavy  growth  or  which  have 
been  unskillfully  pruned  a  pair  of  two-handed  pruning  shears  similar 
to  those  used  for  tree  pruning  may  be  used.  If  these  are  of  good  form, 
kept  sharp,  and  carefully  used  so  as  to  avoid  splitting  the  arms  or 
cutting  too  deeply  into  the  old  wood,  good  work  may  be  done  with  them. 

Disposal  of  Prunings. — After  the  pruning  is  finished,  the  "brush" 
or  cuttings  must  be  removed.  This  is  much  facilitated  if  the  pruners 
are  careful  in  placing  the  wood  they  remove.  The  usual  method  is  to 
place  the  wood  from  two  adjoining  rows  in  the  space  between  them, 
either  in  a  long  line  or  in  piles  between  four  vines. 


52 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


These  rows  or  piles  can  then  be  carried  by  hand  or  with  a  hay  fork 
and  concentrated  in  large  piles  in  the  avenues  or  on  the  borders  of  the 
vineyard,  where  they  are  burned  as  soon  as  sufficiently  dry.  The  heat 
from  these  fires  is  so  great  that  it  sometimes  injures  neighboring  vines, 
especially  if  the  burning  is  deferred  until  the  starting  of  the  buds. 
A  better  method  is  to  use  a  brush  burner.  One  form  of  brush  burner 
is  shown  in  Fig.  21.  This  consists  of  an  iron  truck  with  a  perforated 
bottom.  A  fire  is  started  in  the  truck,  which  is  then  drawn  slowly 


Fig.  21. — Vineyard  brush  burner. 

down  a  free  row  by  a  quiet  horse  trained  to  the  work.  Two  men  collect 
the  "brush"  in  the  adjoining  rowrs  and  throw  it  into  the  moving  truck, 
where  it  burns  without  danger  of  injuring  the  vines,  and  at  a  lower 
temperature  than  in  the  large  piles.  The  ashes  are  distributed  equally 
over  the  vineyard.  The  method  is  difficult  to  adapt  to  trellised  vine- 
yards or  to  vines  with  fruit  canes. 

Gathering  the  brush  with  a  hay  rake  is  sometimes  done,  but  is  not 
satisfactory  and  is  apt  to  injure  the  vines  unless  the  rows  are  far 
apart.  In  some  countries  the  vine  prunings  are  used  for  fuel,  for 
manure,  and  even  for  cattle  feed,  after  cutting  and  crushing.  The 
labor  cost  in  California  seems  at  present  to  prevent  economical  util- 
ization in  any  of  these  ways. 


BULLETIN  241-246  VINE  PRUNING  IN  CALIFORNIA  53 

Principle  of  Economy. — The  skillful  pruner  directs  as  much  as 
possible  of  the  energy  and  growth  of  the  plant  into  the  permanent 
framework  of  the  vine  and  into  its  fruit.  The  unskillful  pruner  allows 
the  vine  to  grow  canes,  arms,  or  branches  where  they  are  not  wanted 
and  which  must  be  cut  off  later.  This  is  not  only  a  complete  loss  to 
the  vine  thus  deprived  of  all  the  removed  material  which  ought  to 
have  gone  into  its  permanent  framework  but  the  large  wounds  made 
are  a  source  of  weakness  and  shorten  the  life  of  the  vine.  The  skillful 
pruner  vitalizes  the  vigor  of  the  vine  by  making  it  bear  all  the  fruit 
it  is  capable  of  bringing  to  perfection.  He  properly  distributes  the 
fruit  buds,  leaving  on  each  cane,  arm,  or  vine  just  the  number  needed, 
without  running  the  risk,  on  the  one  hand,  of  weakening  the  vine  with 
an  oversupply  of  poor  fruit,  or,  on  the  other  hand,  of  forcing  it  to 
excessive  vigor  and  sterility. 

To  avoid  waste  in  the  development  of  a  young  vine,  the  pruner 
must  have  a  clear  idea  of  the  form  he  wishes  to  give  it.  He  must  then, 
by  appropriate  and  timely  removal  of  buds  and  shoots,  force  the  growth 
into  those  parts  which  are  to  form  the  permanent  framework  of  his 
ideal  vine.  No  cane,  arm,  or  division  should  be  allowed  to  grow  more 
than  one  season  which  is  not  destined  to  be  part  of  the  final  skeleton 
of  the  mature  plant.  In  this  way  the  vine  will  not  only  attain  the 
desired  form  but  will  quickly  reach  bearing  stature  and  be  free  from 
the  large  wounds,  which  are  one  of  the  main  causes  of  premature  aging. 
Part  II  of  this  bulletin  will  contain  specific  directions  for  applying 
these  principles  to  the  principal  vines  and  regions  of  California. 


PART  II 

THE  PRACTICE  OF  PRUNING 

Pruning  Systems. — The  systems  of  pruning  applied  to  the  vine  are 
innumerable.  These  systems  differ  in  the  form  given  to  the  body  of 
the  vine  and  in  the  management  of  the  annual  growth.  Some  of  the 
differences  depend  on  variations  in  the  nature  of  the  vines,  on  the 
cultural  and  growing  conditions  of  the  district,  and  on  the  objects  of 
the  grower.  Others  are  unessential  and  merely  a  matter  of  taste.  The 
best  system  is  that  which  is  most  adapted  to  all  the  conditions  of  the 
particular  vineyard.  Any  system  which  does  not  take  into  account 
the  nature  of  the  vine  is  defective. 

Ideals  of  Pruning. — Before  commencing  work  the  pruner  should 
form  a  mental  picture  of  an  ideal  vine  of  the  form  desired.  Vines  are 
subject  to  so  many  accidents  of  weather,  cultivation,  and  disease  that 
even  with  the  greatest  care  and  skill  it  may  be  impossible  to  obtain  a 
single  ideal  vine  in  the  vineyard.  The  ideal  vine,  however,  must  exist 
in  the  pruner 's  mind,  or  all  his  vines  will  be  unnecessarily  defective. 
With  this  ideal  constantly  in  mind,  he  is  able  to  take  such  measures 
as  will,  as  much  as  possible,  direct  the  energies  of  the  vine  in  the  right 
direction  and  counteract  all  contrary  influences,  thus  making  each  vine 
approach  as  nearly  as  possible  the  perfect  model. 

This  mental  ideal  is  particularly  necessary  in  the  treatment  of 
young  vines.  Only  when  it  is  strongly  impressed  on  the  imagination 
is  it  possible  to  use  such  means  and  measures  as  will  most  rapidly  and 
economically  bring  the  vine  to  profitable  maturity. 

In  the  following  account  of  the  principal  systems  of  pruning 
adapted  to  Californian  conditions  a  description  is  first  given  of  an 
ideal  mature  vine  in  full  bearing.  This  is  followed  by  a  discussion 
of  methods  of  handling  a  young  vine  to  make  it  approach  as  nearly 
as  possible  this  ideal,  and  finally  by  an  account  of  the  regular  pruning 
necessary  to  make  the  vine  produce  maximum  crops  to  a  respectable 
old  age. 

Californian  Systems. — The  systems  of  pruning  in  use  in  California 
may  be  divided  into  two  classes,  according  to  the  arrangement  of  the 
arms  on  the  trunk  of  the  vine.  In  the  common  systems  there  is  a 
definite  head  to  the  trunk,  from  which  all  arms  arise  symmetrically  at 


56 


UNIVERSITY   OP    CALIFORNIA — EXPERIMENT   STATION 


nearly  the  same  level.  The  vines  of  these  systems  may  be  called 
"headed  vines."  In  the  other  systems  the  trunk  is  elongated  four 
to  eight  feet  and  the  arms  are  distributed  regularly  along  the  whole 
or  the  greater  portion  of  its  length.  The  vines  of  these  systems,  owing 
to  the  rope-like  form  of  the  trunks,  are  called  ' '  cordons. ' ' 


Wild  vine  from  Caucasia  (Vitis  viniferti). 
The  source  of  our  cultivated  grapes. 

The  headed  vines  are  divided  according  to  the  length  of  the  vertical 
trunk  into  high,  2-3  feet,  medium,  1-1 1/2  feet,  and  l°w>  0-6  inches. 
The  cordons  may  be  vertical  or  horizontal,  according  to  the  direction 
of  the  trunk,  which  is  from  four  to  eight  feet  long.  The  horizontal 
cordons  may  be  single  (unilateral}  or  composed  of  two  branches  ex- 
tending in  opposite  directions  (bilateral}.  Double  and  even  multiple 
vertical  cordons  occur,  but  they  have  no  advantages  and  are  inad- 
visable. 


BULLETIN   241-246  yiNE  PRUNING   IN    CALIFORNIA  57 

The  arrangement  of  the  arras  of  a  headed  vine  may  be  symmetrical 
in  all  directions  at  an  angle  of  about  45  degrees.  Such  a  vine  is  said 
to  be  "  vase-formed,"  though  the  hollow  center  which  this  term  implies 
is  not  essential.  This  is  the  form  used  in  the  great  majority  of  our 
vineyards  whether  of  wine,  raisin,  or  shipping  grapes.  It  is  suitable 
for  the  "square"  system  of  planting  and  cross-cultivation.  Where 
vines  are  planted  in  the  avenue  system,  particularly  when  trellised, 
and  where  cross-cultivation  is  impossible,  the  arms  are  given  a  "fan- 
shaped"  arrangement  in  a  vertical  plane.  This  arrangement  is  essen- 
tial for  the  economical  working  of  trellised  vines. 

On  the  vertical  or  upright  cordon  the  arms  are  arranged  at  as 
regular  intervals  as  possible  on  all  sides  of  the  trunk  from  the  top  to 
within  twelve  or  fifteen  inches  of  the  bottom.  On  the  horizontal  cordon 
the  arms  are  arranged  similarly,  but  as  nearly  as  possible  on  the  upper 
side  only  of  the  trunk. 

Each  of  these  systems  may  again  be  divided  into  two  sub-systems, 
according  to  the  management  of  the  annual  growth  or  canes.  In  one, 
spurs  of  one,  two,  or  three  eyes  are  left  for  fruit  production.  This 
system  is  called  short  or  spur  pruning.  In  the  other,  long  canes  are 
left  for  fruit  production  (long  or  cane  pruning}.  In  rare  cases  an 
intermediate  form  is  adopted  in  which  long  spurs  or  short  canes  of 
five  or  six  eyes  are  left.  In  cane  pruning,  each  fruit  cane  is  accom- 
panied by  one  or  two  short  renewal  spurs.  These  must  also  accompany 
half-long  pruning.  Systems  of  pruning,  where  only  long  canes  are  left 
without  renewal  spurs,  are  not  in  use  in  California.  In  all  systems 
replacing  spurs  are  left  wherever  and  whenever  needed. 

Other  modifications  are  introduced  by  the  manner  of  disposal  of 
the  fruit  canes.  These  may  be  tied  up  vertically  to  a  stake  driven  at 
the  foot  of  each  vine,  or  bowed  in  a  circle  and  tied  to  this  same  stake, 
or  they  may  be  tied  laterally  to  wires  stretching  along  the  rows  in  a 
horizontal,  ascending,  or  descending  direction. 

The  different  systems  differ  therefore  in:  (1)  the  shape,  length, 
and  direction  of  the  trunk;  (2)  the  arrangement  of  the  arms;  (3)  the 
use  of  fruit  spurs  or  fruit  canes  with  renewal  spurs;  (4)  the  disposal 
of  the  fruit  canes. 

The  principal  possibilities  are  shown  in  the  following  table  : 

A.  HEAD  PRUNING:  VASE  FORM 


i    TT   ti  *       v       f         ^1  (a)   ^"ruit  spurs  or 

o    ™   r  bj  ™u>,  1(6)  Half-long  canes  and  renewal  spurs  or 

3.  Lo^Tunk       1          J  <c>   Fruit  Ca"6S  and  renewal 


58 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


B.  HEAD  PRUNING:  FAN  SHAPED;  TRELLISED 

1.  High  trunk:  Fruit  canes  and  renewal  spurs;  canes  descending. 

2.  Medium  trunk:  Fruit  canes  and  renewal  spurs;  canes  horizontal  or  ascending. 

C.  CORDON  PRUNING 

1.  Vertical:  Spur;  half-long;  cane. 

2.  Horizontal-unilateral:  Spur;  half -long;  cane. 

3.  Horizontal -bilateral:  Spur;  half -long;  cane. 

All  possible  combinations  indicated  by  this  table  represent  twenty- 
four  variations.  Some  of  these  combinations,  however,  are  not  used 
and  some  are  rare.  The  common  ones  are  shown  in  Figs.  22,  23,  24,  25, 
and  26. 


ABC 

Fig.  22. — Forms  of  head  pruning:  A,  spur  pruning  with  high  trunk;  B,  spur 
pruning  with  medium  trunk;  C,  half -long  with  medium  trunk. 

Fig.  22  B  represents  a  headed,  vase-formed  vine,  with  a  medium  trunk  and 
short  fruit  spurs.  This  is  the  common  system  used  in  all  parts  of  California, 
and  is  suited  for  all  small  growing  vines  which  bear  on  the  lower  buds,  for  most 
wine  grapes  and  for  Muscats.  The  unit  of  pruning  in  this  case  is  a  fruit  spur 
of  1,  2,  or  3  internodes,  according  to  the  vigor  of  the  variety  and  of  the  indi- 
vidual cane. 

Fig.  22  A  differs  from  22  B  only  in  the  higher  trunk  and  longer  arms.  It  is 
commonly  used  for  Tokay  and  other  large  growing  varieties,  especially  when 
growing  in  rich  soil  and  when  planted  far  apart. 

Fig.  22  C  has  the  same  form  of  body  as  A  and  B,  except  that  the  arms  are 
somewhat  less  numerous.  The  unit  of  pruning  is  a  short  fruit  cane  of  four  to 
five  internodes,  accompanied  by  a  renewal  spur  of  one  internode.  It  is  suited 
for  vigorous  table  grapes,  which  do  not  bear  well  on  short  spurs,  being  used 
especially  for  the  Cornichon  and  Malaga  in  rich  soil.  This  is  a  difficult  system 
to  keep  in  good  shape  owing  to  the  tendency  for  all  the  vigor  to  go  to  the 
growth  on  the  ends  of  the  fruit  canes.  It  is  difficult  to  obtain  vigorous  canes  on 
the  renewal  spurs.  Occasional  short  pruning  is  usually  necessary  to  keep  the 
vines  in  proper  shape. 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


59 


Fig.  23  A  is  similar  to  22  C  in  form,  but  the  number  of  arms  is  still  further 
reduced  to  2,  3,  or  at  most  4.  The  unit  of  pruning  is  a  fruit  cane  of  2^  to  3% 
feet  with  its  renewal  spur.  Owing  to  the  length  of  the  fruit  canes,  they  require 
support  and  are  tied  to  a  high  stake. 


A  B 

Tig.  23. — Forms  of  head  pruning:  A,  vertical  fruit  canes  and  renewal  spurs; 
B,  bowed  fruit  canes  and  renewal  spurs. 

This  method  is  used  in  a  large  number  of  vineyards  with  Sultanina, 
Sultana,  and  certain  wine  grapes,  especially  Semillon  and  Cabernet. 
It  is  not  to  be  recommended,  as  it  has  several  serious  defects. 

The  difficulty  of  obtaining  new  wood  from  the  renewal  spurs  is  even 
greater  than  in  the  system  shown  in  Fig.  22  C.  The  length  and  vertical 
position  of  the  fruit  canes  cause  the  main  growth  and  vigor  of  the  vine 
to  be  expended  on  the  highest  shoots.  (See  Physiological  Principles 
5  and  6,  p.  26,  Pt.  I)  The  renewal  spurs  are  thus  so  shaded  that,  even 
though  their  buds  start,  the  shoots  make  but  a  weak  growth.  The 


60  UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 

result  is  that  at  the  following  pruning  all  the  good  new  wood  is  at  the 
top  of  the  fruit  canes  of  the  previous  year,  where  it  cannot  be  utilized. 
The  pruner  then  has  to  choose  between  reverting  to  spur  pruning  and 
getting  no  crop,  or  using  the  weak  growth  from  the  renewal  spurs  for 
fruit  canes,  in  which  case  he  may  get  blossoms  but  little  or  no  fruit 
of  any  value. 

Other  defects  of  this  method  are  that  the  fruiting  shoots  are  ex- 
cessively vigorous  and  therefore  often  tend  to  drop  their  blossoms  with- 
out setting,  and  the  fruit  when  produced  is  massed  together  so  that 
it  ripens  unevenly  and  is  difficult  to  gather.  It  also  requires  a  tall 
and  expensive  stake. 

Fig.  23  B  represents  an  improvement  on  the  last  system.  It  differs 
only  in  the  method  of  treating  the  fruit  canes.  These  are  bent  over  in 
the  form  of  a  circle  and  tied  by  their  middle  part  to  a  stake  which  may 
be  smaller  and  lower  than  that  needed  for  the  vertical  canes. 

This  bowing  of  the  canes  has  several  useful  effects.  The  change 
of  direction  moderates  the  tendency  of  the  vigor  of  the  vine  to  expend 
itself  only  on  the  terminal  shoots.  More  shoots  are  therefore  formed 
on  the  fruit  canes  and  as  their  vigor  is  somewhat  decreased  they  tend 
to  be  more  fruitful.  The  slight  mechanical  injury  caused  by  the  bend- 
ing operates  in  the  same  direction.  (See  Physiological  Principle  4, 
p.  25,  Pt.  I.) 

The  excess  of  vigor  being  thus  diverted  from  the  fruit  canes  causes 
the  renewal  spurs  to  form  vigorous  shoots,  which  soon  grow  above  the 
fruit  shoots  and  obtain  the  light  and  air  they  need  for  their  proper 
development.  This  method  is  used  successfully  for  certain  wine  grapes 
such  as  Riesling,  Cabernet,  and  Semillon.  It  is  unsuited  to  large 
vigorous  varieties  or  for  vines  on  rich  soil  planted  wide  apart.  In 
these  cases  two  fruit  canes  are  usually  insufficient,  and,  if  more  are 
used,  the  grapes  and  leaves  are  so  massed  together  that  they  are  subject 
to  mildew  and  do  not  ripen  evenly.  The  bowing  and  tying  of  the 
qanes  requires  considerable  skill  and  care  on  the  part  of  the  workmen. 

The  body,  arms,  and  annual  pruning  of  the  system  shown  in  Fig.  24 
are  similar  to  those  of  Fig.  23,  with  the  exception  that  the  arms  are 
given  a  fan-shaped  arrangement  in  one  plane.  It  differs  in  the  dis- 
posal of  the  fruit  canes,  which  are  supported  by  a  trellis  stretching 
along  the  row  from  vine  to  vine. 

This  method  is  largely  used  for  the  Sultanina  (Thompson's  Seed- 
less), and  is  the  best  system  for  vigorous  vines  which  require  long 
pruning,  wherever  it  is  possible  to  dispense  with  cross-cultivation.  It 
is  also  suitable  for  any  long-pruned  varieties  when  growing  in  fertile 
soil. 


BULLETIN  241-246 


VINE   PRUNING    IN    CALIFORNIA 


61 


62  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Fig.  25  is  a  photograph  of  a  four-year-old  Emperor  vine,  illus- 
trating the  vertical  cordon  system.  It  consists  of  an  upright  trunk 
£1/2  feet  high  with  short  arms  and  fruit  spurs  scattered  evenly  and 
symmetrically  from  the  top  to  within  fifteen  inches  of  the  bottom. 
This  system  is  used  in  many  Emperor  vineyards  in  the  San  Joaquin 


Fig.  25. — Single  vertical  cordon  with  fruit  spurs. 

Valley.  Its  advantages  are  that  it  allows  the  large  development  of 
the  vine  and  the  large  number  of  spurs  which  the  vigor  of  the  Emperor 
demands  without,  on  the  one  hand,  crowding  the  fruit  by  the  prox- 
imity of  the  spurs  or,  on  the  other,  spreading  the  vine  so  much  that 
cultivation  is  interfered  with.  It  also  permits  cross-cultivation. 

One  of  its  defects  is  that  the  fruit  is  subjected  to  various  degrees 
of  temperature  and  shading  in  different  parts  of  the  vine  and  the 
ripening  and  coloring  are  often  uneven.  A  more  vital  defect  is  that 


BULLETIN  241-246  VINE  PRUNING  IN  CALIFORNIA  63 

it  cannot  be  maintained  permanently.  The  arms  and  spurs  at  the  top 
of  the  trunk  tend  to  absorb  the  energies  of  the  vine  and  the  lower  arms 
and  spurs  become  weaker  each  year  until  finally  no  growth  at  all  is 
obtained  below.  After  several  years  most  of  the  vines  therefore  lose 
their  character  of  cordons  and  become  simply  headed  vines  with  ab- 
normally long  trunks.  (See  Figs.  64,  65.) 

The  cordon  can  be  reestablished  in  this  case  by  allowing  a  vigorous 
sucker  to  develop  one  year  from  which  to  form  a  new  trunk  the  next. 
The  following  year  the  old  trunk  is  removed  entirely.  An  objection 
to  this  method  is  that  it  makes  very  large  wounds  in  the  most  vital 
part  of  the  vine — the  base  of  the  trunk. 


Fig.  26. — Unilateral  horizontal  cordon  with  fruit  spurs. 

Fig.  26  is  a  photograph  of  a  four-year-old  Colombar  vine,  illus- 
trating the  unilateral,  horizontal  cordon  system.  It  consists  of  a  trunk 
about  seven  feet  long,  supported  horizontally  by  a  wire  two  feet  from 
the  ground.  Arms  and  spurs  are  arranged  along  the  whole  horizontal 
part  of  the  trunk. 

This  system  accomplishes  the  same  purposes  as  the  vertical  cordon. 
It  allows  a  large  development  of  the  vine  and  of  numerous  fruit  spurs 
without  crowding.  It  is  superior  to  the  vertical  cordon  in  the  distri- 
bution of  the  fruit,  which  is  all  exposed  to  approximately  the  same 
conditions  owing  to  the  uniform  distance  of  the  fruit  spurs  from  the 
ground.  All  parts  of  the  trunk  producing  an  annual  growth  of  wood 
and  fruit  are  equally  exposed  to  light  and  the  tendency  of  the  growth 
to  occur  principally  at  the  part  of  the  trunk  farthest  removed  from 
the  root  is  counteracted  by  the  horizonal  position.  There  is  not  the 
same  difficulty  therefore  in  maintaining  this  form  of  vine  permanently 
that  there  is  with  the  vertical  cordon. 


64  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

This  system  should  not  be  used  for  small  weak  vines,  whether  the 
weakness  is  a  characteristic  of  the  variety  or  due  to  the  nature  of  the 
soil.  It  is  suited  only  to  very  vigorous  varieties,  such  as  Emperor, 
Almeria,  and  the  Persian  grapes,  when  these  are  growing  far  apart 
in  rich,  moist  soil. 

Periods  of  Development. — The  first  year  in  the  life  of  the  vine  is 
devoted  to  developing  a  vigorous  root  system ;  the  next  two  or  three 
years  to  building  up  a  shapely  trunk  and  head,  and  a  like  period  to 
forming  the  full  complement  of  arms.  At  the  end  of  from  five  to  nine 
years  the  framework  of  the  vine  is  complete  and  should  undergo  no 
particular  change  of  shape  except  a  gradual  thickening  of  trunk  and 
arms. 

There  are,  therefore,  several  periods  in  the  life  of  the  vine,  with 
varying  objects,  and  the  methods  of  pruning  must  vary  accordingly. 
These  periods  do  not  correspond  exactly  to  periods  of  time,  so  that  it 
may  be  misleading  to  speak  of  pruning  a  two-year-old1  or  a  three- 
year-old  vine.  One  vine  under  certain  conditions  will  reach  the  same 
stage  of  development  in  two  years  that  another  will  reach  only  in  three 
or  four  years  under  other  conditions.  The  range  of  time  of  these 
periods  is  about  as  follows : 

First  period — Formation  of  a  strong  root  system  1  to  2  years 

Second  period — Formation  of  stem  or  trunk  1  year 

Third  period — Formation  of  head  2  to  3  years 

Fourth  period — Complete  development  of  the  arms  2  to  3  years 

Total  time  of  formation  of  framework  6  to  9  years 

Jnder  exceptionally  favorable  conditions  the  first  and  second 
periods  may  be  included  in  the  first  year  and  a  completely  formed 
vine  may  be  obtained  in  five  years. 

Before  Planting. — Cuttings,  one-year-old  rooted  vines,  or  bench 
grafts  are  used  for  planting.  In  all  cases  they  need  some  attention 
from  the  pruner.  In  Fig.  27  are  shown  the  three  forms  of  cuttings 
used  in  California.  They  differ  only  in  length.  The  shortest  eight 
to  ten  inches,  are  best  suited  for  planting  in  the  nursery;  those  of 
twelve  to  fourteen  inches  for  planting  in  the  field.  The  longest  cut- 
tings, sixteen  to  eighteen  inches,  are  to  be  recommended  only  for  the 
driest  soils.  In  all  cases  they  are  cut  at  the  bottom  just  below  a  bud. 
This  facilitates  the  healing  over  of  the  base,  as  roots  and  healing 
tissue  form  most  abundantly  near  a  node.  The  top  may  be  cut  just 

1  Age  of  Vines. — There  is  a  diversity  of  usage  in  denoting  the  age  of  a  vine. 
In  some  localities  a  one-year-old  vine  means  a  vine  that  is  in  its  first  year;  in 
others  it  means  a  vine  that  has  completed  its  first  year  and  is  in  its  second.  The 
former  method  is  adopted  here  as  the  most  convenient. 


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VINE   PRUNING   IN    CALIFORNIA 


65 


above  a  bud,  so  as  to  leave  the  protecting  diaphragm  or  about  one  inch 
of  internode,  as  in  the  figure. 

Fig.  28  shows  a  bundle  of  good  one-year-old  rooted  vines  as  they 
are  usually  prepared  at  the  nursery.  Before  planting  they  must  be 
pruned.  The  method  of  pruning  depends  on  the  size  and  shape  of  the 
vine  and  on  the  method  of  planting  adopted. 


Fig.  27. — Forms  of  cuttings. 


Fig.  28. — One-year-old  rooted  vines. 


Fig.  29  shows  a  good  rooted  vine  of  average  size  having  a  single 
cane  at  the  top  and  several  good  roots  at  the  bottom.  The  usual  way 
to  prune  this  is  to  shorten  the  cane  to  one  or  two  buds  and  the  roots 
to  two  or  four  inches,  according  to  their  size.  Shortening  the  cane 
makes  the  vine  less  liable  to  dry  out  before  rooting  and  forces  the 
growth  from  the  lower  buds  which  produce  more  vigorous  shoots.  The 
roots  are  shortened  so  that  there  will  be  no  danger  of  the  ends  being 
turned  upwards  when  planted.  If  they  are  to  be  planted  in  a  large 
hole,  they  may  be  left  as  long  as  five  or  six  inches ;  if  to  be  planted  with 
a  crowbar  or  dibble,  they  must  be  cut  back  to  half  an  inch. 

There  is  little  if  any  advantage  in  leaving  long  pieces  of  roots. 
They  are  not  feeding  roots  and  are  of  no  use  to  the  vine  until  they 


UNIVERSITY   Of   CALIFORNIA — EXPERIMENT    STATION 


develop  feeding  rootlets.  This  they  will  do  as  well  or  better  if  short- 
ened instead  of  being  left  full  length.  The  main  advantage  of  a  rooted 
vine  over  a  cutting  is  that  it  forms  rootlets  more  easily  and  rapidly. 
There  may  be  a  slight  advantage  in  leaving  three  or  four  inches  of  the 
sound  well  grown  roots,  as  the  reserve  matters  they  contain  probably 
promote  a  better  growth  of  rootlets,  but  little  or  no  difference  has  been 
noted  between  the  growth  of  vines  of  which  the  roots  have  been  short- 


Fig.  29. — Booted  vine  with 
single  cane. 


Fig.  30. — Booted  vine  with 
two  canes. 


ened  to  one-half  inch  and  those  which  have  been  left  longer.  "Where 
the  roots  are  left  long,  moreover,  more  care  and  time  are  needed  in 
planting. 

If  the  rooted  vine  has  several  canes,  all  but  one  should  be  removed 
entirely,  and  this  one  shortened  to  one  or  two  eyes.  The  one  left  should 
be  that  which  is  strongest,  has  the  best  buds,  and  is  the  best  placed. 
Fig.  30  shows  the  removal  of  a  cane  growing  horizontally  and  two 
buds  left  on  a  vertical  cane.  Where  a  horizontal  cane  is  left  it  should 
be  cut  back  to  the  base  bud.  Otherwise  the  main  growth  may  occur  at 
a  higher  bud  and  the  vine  will  have  a  crook  which  will  result  in  a  badly 
formed  trunk. 


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67 


If  canes  are  growing  from  different  joints,  as  in  Fig.  31,  it  is  usually 
best  to  leave  the  lowest  cane  if  they  are  equally  vigorous.  This  brings 
the  buds  from  which  growth  will  come  nearer  to  the  roots  and  leaves 
less  of  the  original  cutting,  which  are  advantages.  The  upper  joint 
between  the  canes  is,  moreover,  often  more  or  less  decayed  or  imperfect. 

Fig.  32  shows  a  vine  pruned  and  ready  for  planting.  Bench 
grafted  vines  are  pruned  in  exactly  the  same  way,  but  in  this  case  it 
is  necessary  to  take  great  care  that  all  roots  from  near  or  above  the 
union  and  all  canes  from  near  or  below  the  union  are  removed. 


Fig.  31. — Booted  vine  with 
canes  at  two  levels. 


Fig.  32 — Hooted  vine  pruned 
ready  for  planting. 


Fig.  33  shows  a  vine  grown  in  the  nursery  from  an  unnecessarily 
long  cutting.  It  was  grown  in  warm,  well  drained  soil,  so  that  roots 
have  formed  at  three  levels  from  different  nodes.  Even  in  this  soil, 
however,  the  conditions  were  not  favorable  for  root  growth  at  the 
bottom,  so  the  last  two  nodes  have  formed  no  roots.  If  the  cutting 
had  been  of  five  nodes  instead  of  eight,  it  would  have  made*  a  much 
better  vine.  The  roots  would  have  been  less  numerous  but  more  vigor- 
ous. Such  a  vine  can  be  pruned  in  one  of  three  ways,  according  to  the 


68 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


character  of  the  ground  in  which  it  is  to  be  planted.  In  any  case,  the 
bottom  two  joints,  without  good  roots,  are  cut  off.  If  the  soil  where 
the  vine  is  to  be  planted  is  deep  and  dry,  the  roots  at  the  next  three 
joints  may  be  left  and  shortened  to  about  one  inch,  as  indicated  in  the 
figure.  The  roots  are  so  numerous  that  none  of  them  have  grown  large 
(see  Physiological  Principles,  p.  25,  Pt.  I),  and  nothing  would  be 
gained  by  leaving  them  longer.  For  ordinary  soils  it  would  be  better 
to  remove  the  lower  three  joints  and  for  wet  soils  the  lower  five. 


Fig.  33. — Nursery  vine  with 
roots  at  different  levels. 


Fig.  34. — Eesult  of  planting  too 
deep. 


Fig.  34  shows  the  result  of  planting  an  unnecessarily  long  cutting 
or  rooted  vine.  It  represents  the  lower  part  of  the  underground  por- 
tion of  a  vine  two  or  three  years  old.  The  cutting  or  rooted  vine  was 
at  least  three  joints  too  long,  and  the  lowest  part  not  only  furnishes 
no  roots  of  any  value  but  is  liable  to  decay,  which  may  spread  into  the 
rest  of  the  vine. 

Fig.  35  shows  the  root  growth  during  the  first  year  in  the  field  of 
a  rooted  vine  of  which  the  roots  had  been  properly  pruned  and  planted 
at  the  right  depth. 

Planting. — Cuttings  made  as  directed  are  planted  with  the  second 
bud  at  the  level  of  the  ground,  leaving  only  one  bud  above.  Rooted 
vines -are  planted  with  the  two  buds  just  above  the  surface.  Bench 


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69 


In 


grafts  are  planted  with  the  union  just  one  inch  above  the  surface, 
the  last  case  the  soil  must  be  hilled  up  so  as  to  cover  the  union. 

First  Growing  Season. — The  treatment  during  the  first  spring  and 
summer  will  depend  on  what  growth  the  vines  are  expected  to  make 
and  on  whether  the  vines  are  staked  the  first  year. 

With  cuttings  and  with  both  rooted  vines  and  grafts  where  the 
growth  will  be  moderate  staking  the  first  year  is  unnecessary,  though 
it  has  some  slight  advantages.  In  these  cases  no  pruning  of  any  kind 
is  necessary  until  the  winter  following  the  planting,  except  in  the  case 


Fig.    35. — Eoots   of   a  young  vine  that   had  been   properly   pruned   before 
planting. 

of  bench  grafts.  The  pruning  in  the  last  case  is  confined  to  the  re- 
moval of  the  suckers  from  the  stock  and  roots  from  the  scion.  If  the 
stocks  have  been  well  disbudded  by  the  nurseryman,  few  suckers  will 
develop.  In  moist  soil  the  scion  roots  may  develop  vigorously,  and 
must  be  removed  before  they  grow  too  large  or  they  may  prevent  the 
proper  development  of  the  resistant  roots. 

The  removal  of  roots  should  usually  be  done  some  time  in  July. 
For  this  purpose  the  hill  of  soil  is  scraped  away  from  the  union  and 
after  the  scion  roots  and  suckers  are  removed  it  is  replaced.  In  this 
second  hilling  up  the  union  should  be  just  barely  covered  so  that  the 


70 


UNIVERSITY    OP    CALIFORNIA EXPERIMENT    STATION 


soil  around  the  union  will  be  dry  and  unfavorable  to  a  second  growth 
of  roots.  Later  in  the  season,  about  September,  the  soil  should  be 
removed  entirely  from  around  the  union  and  any  new  roots  that  may 
have  formed  removed.  The  union  is  then  left  exposed  to  harden  and 
mature,  so  that  it  will  pass  the  winter  without  injury. 


"is 


Fig.  36. — Growth  of  vine  during  the  first  summer. 

Fig.  36  shows  a  grafted  vine  in  July  after  the  union  has  been  un- 
covered for  root  cutting.  It  represents  a  good  average  vine  at  this 
period.  Such  a  vine  will  usually  support  itself  without  a  stake  but 
if  a  stake  is  used  it  should  be  tied  to  it  loosely.  If  the  main  shoot  is 
kept  upright,  it  will  be  easier  to  produce  a  well  formed  vine. 

No  disbudding,  thinning  of  shoots,  or  topping  need  be  done  in  this 
case.  The  object  is  to  have  as  abundant  a  growth  of  foliage  as  possible 


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71 


in  order  to  stimulate  a  vigorous  and  abundant  root  development.  (See 
Physiological  Principle  No.  1,  p.  25,  Pt.  I.) 

In  some  cases,  where  very  good  rooted  vines  of  vigorous  varieties 
are  planted  in  rich  soil  abundantly  supplied  with  water,  it  is  desirable 
to  disbud  the  vine  early  in  order  to  throw  all  its  energies  into  the  single 
main  cane.  In  such  cases  staking  before  or  just  after  planting  are 
necessary,  and  methods  similar  to  those  described  for  the  second  season 
are  used. 

First  Winter  Pruning. — At  the  end  of  the  first  growing  season  an 
average  good  vine  will  have  produced  from  three  to  five  canes,  the 
longest  of  which  will  be  from  two  to  three  feet  long.  (See  Fig.  37  A.) 


Fig.  37. — Vine  at  end  of  first  growing  season.  First  winter  pruning;  A, 
before  pruning;  c,  c,  places  for  making  cuts;  B,  after  pruning  and  staking. 

Soon  after  the  leaves  have  fallen  in  December  or  early  in  January, 
the  vines  should  be  pruned.  The  method  is  precisely  similar  to  that 
used  for  rooted  vines  before  planting  except  that  the  main  roots  are 
not  touched.  All  the  canes  are  removed  entirely  except  one.  This  one 
should  be  well  matured,  at  least  at  the  base,  and  should  have  well 
formed  eyes.  It  is  shortened  to  two  eyes.  (See  Fig.  37  B.)  It  is  well 
also  to  cut  off  all  shallow  roots  within  three  or  four  inches  of  the  sur- 
face. This  is  necessary  in  the  case  of  grafted  vines  if  any  have  escaped 
the  summer  root  cutting. 

Some  of  the  vines  may  have  made  an  exceptionally  large  growth. 
Such  vines  may  sometimes  possess  a  cane  large  enough  from  which 
to  start  the  trunk  in  the  way  described  later  for  the  second  winter 
pruning. 

Staking. — If  the  vines  have  not  been  staked  before,  the  stakes 
should  be  driven  soon  after  pruning  and  before  the  starting  of  the 
buds. 

In  order  to  preserve  the  alignment  of  the  vineyard  the  stakes  should 
be  driven  on  the  same  side  of  every  vine  at  a  uniform  distance.  The 


72  UNIVERSITY   OP    CALIFORNIA — EXPERIMENT   STATION 

best  distance  is  about  two  inches.  If  driven  closer  they  may  injure 
large  roots,  or  even  the  main  underground  stem  if  the  vines  have  not 
been  carefully  planted  vertically  or  slanting  toward  the  side  on  which 
the  stake  is  to  be  placed. 

The  side  on  which  the  stake  should  be  placed  depends  on  the 
direction  of  the  prevailing  winds  during  the  growing  season.  This 
side  is  the  leeward.  That  is,  the  stake  should  be  so  placed  that  the 
wind  will  press  the  vine  toward  the  stake  instead  of  away  from  it.  This 
will  much  facilitate  the  work  of  keeping  the  vine  upright  and  attached 
to  the  stake.  If  the  vine  is  on  the  other  side  the  pressure  of  the  wind 
will  stretch  the  string  tight  and  the  swaying  of  the  vine  will  gradually 
wear  the  string  until  it  breaks,  necessitating  retying.  By  carefully 
observing  this  rule  very  few  vines  will  require  retying  even  if  weak 
material  like  binding  twine  is  used. 

Second  Summer  Pruning. — Before  the  starting  of  the  buds,  in  the 
spring  following  the  planting,  most  of  the  vines  appear  about  the  same 
as  when  they  were  planted.  ( See  Fig.  38. )  There  is,  however,  a  very 
notable  difference  in  that  they  have  well  developed  root  systems  in  the 
soil  where  they  were  formed.  The  result  is  that  they  make  a  much 
more  prompt  and  early  start  and  will  produce  a  much  larger  growth 
than  they  did  the  first  season.  For  this  reason  they  require  very  care- 
ful attention  from  the  pruner  during  the  spring  and  summer  of  the 
second  season.  Vines  neglected  at  this  time,  in  this  respect,  may  make 
as  large  a  growth,  but  a  large  part  of  it  will  be  wasted,  the  vines  will 
be  misformed,  and  it  will  require  from  one  to  two  years  longer  to  de- 
velop a  suitable  framework  and  to  bring  them  into  bearing,  even  though 
they  are  properly  handled  during  subsequent  years.  The  more  vigor- 
ous the  vines  the  more  necessary  it  is  to  handle  them  properly  during 
this  period. 

The  main  object  during  this  second  growing  season  is  to  develop  a 
single,  strong,  vigorous  and  well  ripened  cane  from  which  to  form  the 
permanent  trunk  of  the  vine. 

This  is  done  by  concentrating  all  the  energies  of  the  vine  into  the 
growth  of  a  single  shoot.  As  soon  as  the  buds  start  or  when  the  most 
precocious  has  developed  a  shoot  of  a  few  inches  in  length,  the  vines 
should  be  disbudded  (Fig.  38  A).  This  consists  in  rubbing  off  with 
the  hand  all  buds  and  shoots  except  the  largest  and  best  placed.  The 
lowest,  upright  shoot  is  usually  the  best.  Leave  only  those  which  will 
make  a  straight  vine.  It  is  better  to  leave  a  less  developed  bud  than 
a  shoot  which,  when  it  grows,  will  make  an  awkward  crook  with  the 
underground  stem. 


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73 


After  this  disbudding,  the  shoot  left  will  grow  rapidly,  as  it  re- 
ceives all  the  energies  of  the  root  system.  When  it  has  grown  from 
ten  to  fifteen  inches  it  should  be  tied  to  the  stake  (Fig.  38  B).  Unless 
this  is  done  it  is  liable  to  be  broken  off  by  a  heavy  wind,  owing  to  its 
soft,  succulent  texture. 

At  the  tying  up  of  the  reserved  shoots  all  new  shoots  which  have 
developed  since  the  first  disbudding  should  be  removed.  The  shoots 
should  be  tied  up  loosely,  as  they  are  soft  and  easily  injured,  and  they 
should  be  brought  around  carefully  to  the  windward  side  of  the  stake. 


Fig.  38. — Growth  and  treatment  of  the  vine  during  the  second  season,  c,  c, 
place  where  shoots  are  removed. 

The  shoots  will  require  tying  once  more  when  they  have  grown 
another  foot  or  eighteen  inches.  There  will  then  be  two  ties,  one  at 
two  or  three  inches  from  the  top  of  the  stake  and  the  other  at  about 
the  middle.  If  the  vines  have  a  tall  stake  and  are  to  be  headed  very 
high,  another  tying  higher  up  may  be  needed  later  (Fig.  38  C). 

"With  vines  making  only  a  moderate  growth,  no  other  pruning  will 
be  needed  until  the  winter.  Exceptionally  vigorous  vines,  however, 
may  make  a  cane  eight,  ten  or  more  feet  long.  Such  a  cane  is  heavy 
and  is  very  likely  to  break  the  ropes  by  which  it  is  attached  to  the 
stake.  In  this  case  it  may  break  off  at  the  bottom,  or  at  least  will  form 
an  awkward  crook  near  the  ground  when  it  matures.  In  either  case 
it  is  difficult  to  form  a  good  trunk  the  following  year.  Even  when  the 
ties  do  not  break,  the  cane  will  not  be  well  suited  for  the  commencement 


74  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

ft 

of  a  trunk,  as  the  joints  will  be  so  long  that  it  will  be  impossible  to 
leave  enough  well  placed  buds  at  the  winter  pruning. 

Both  these  difficulties  are  avoided. by  timely  topping.  When  such 
vigorously  growing  canes  have  grown  twelve  or  eighteen  inches  above 
the  top  of  the  stake  they  are  cut  back  about  level  with  the  stake  ( Fig. 
38  D).  This  is  most  conveniently  done  with  a  long-bladed  knife  or 
piece  of  split  bamboo.  After  topping,  the  cane  ceases  to  grow  in  length 
and  laterals  start  at  most  of  the  joints.  It  is  less  exposed  to  the  action 
of  the  wind  and  the  laterals  supply  the  buds  needed  for  forming  the 
vine  at  the  winter  pruning. 

The  result  of  the  second  season's  growth,  then,  has  been  to  produce 
a  single  vigorous  cane  with  or  without  laterals.  This  is  the  cane  which 
is  to  develop  into  the  final  and  permanent  trunk  of  the  vine.  It  must 
not  only  be  large  and  vigorous  but  must  be  properly  matured.  If  the 
vine  is  allowed  to  grow  too  late  in  the  season,  an  early  frost  may  de- 
stroy the  unmatured  cane  and  much  of  the  results  of  the  year 's  growth 
will  be  wasted.  Such  a  frost  may  indeed  kill  the  entire  vine.  Grafted 
vines  are  particularly  liable  to  injury  from  this  cause,  as,  if  they  are 
killed  down  to  the  union,  they  are  completely  ruined.  Ungrafted  vines 
when  killed  to  the  ground  may  be  renewed  from  a  sucker  the  following 
year.  This  sucker,  however,  is  likely  to  grow  with  such  vigor  that  it  is 
even  more  liable  to  injury  from  an  autumn  frost  than  the  original 
shoot. 

This  late  growth  is  much  more  likely  to  occur  with  young  vines  than 
with  old.  The  old  vines  stop  growing  earlier  because  their  energies 
are  directed  into  the  crop  and  as  they  produce  a  larger  amount  of 
foliage  they  draw  more  upon  the  moisture  of  the  soil,  which  therefore 
dries  out  earlier. 

Late  growth  of  the  young  vines  must  be  prevented  and  the  wood 
matured  before  frost  if  .possible.  This  is  accomplished  by  means  which 
promote  the  drying  of  the  soil  in  autumn.  Late  irrigations  should  be 
avoided.  Cultivation  should  usually  stop  by  midsummer.  In  very 
moist,  rich  soils  it  is  often  an  advantage  to  grow  corn,  sunflowers,  or 
similar  crops  between  the  rows  of  vines  to  take  off  the  surplus  moisture. 
In  some  cases  it  is  good  practice  to  let  the  summer  weeds  grow  for  the 
same  purpose. 

Second  Winter  Pruning. — With  vines  which  have  been  treated  as 
described,  and  to  which  no  accident  has  happened,  the  second  winter 
pruning  is  very  simple.  It  consists  only  in  cutting  back  the  single 
cane  which  has  been  allowed  to  grow  to  the  height  at  which  it  is  desired 
to  head  the  vine. 


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75 


Fig.  39  represents  a  vine  which  has  been  cut  back  to  form  a  low 
medium  head.  It  consists  of  a  single  cane  which  with  the  older  wood 
at  the  base  reaches  nearly  to  the  top  of  the  stake,  or  fifteen  inches.  If 
properly  treated  this  will  develop  into -a  vine  with  a  trunk  of  about 
twelve  inches,  though  this  length  can  be  modified  slightly,  as  will  be 
explained  later. 

This  cane  consists  of  about  seven  or  eight  joints  or  internodes,  with 
an  equal  number  of  well  formed  eyes  and  an  indefinite  number  of 


Fig.  39. — Second  winter  pruning  for  head  of  medium  height. 

dormant  buds,  principally  near  the  base  of  the  cane  or  junction  of  the 
one  and  two-year-old  wood.  Only  the  buds  on  the  upper  half  of  this 
cane  should  be  allowed  to  grow.  These  buds — about  four — should  give 
six  to-eight  bunches  of  grapes  and  four,  six,  or  eight  shoots  from  which 
to  form  the  spurs  at  the  following  winter  pruning. 

Fig.  40  represents  a  vine  which  has  been  cut  back  to  form  a  high 
head.  The  cane  is  about  twenty-four  inches  long  and  may  be  used  to 
form  a  trunk  eighteen  inches  high,  though  this  height  can  be  modified 
as  in  the  last  case.  As  with  the  shorter  cane,  only  the  buds  on  the 
upper  half  will  be  allowed  to  produce  shoots.  These — about  six — 
should  give  ten  to  twelve  bunches  and  the  shoots  necessary  for  the 
formation'  of  spurs. 


76 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


Fig.  41  represents  a  vigorous  vine  which  had  been  topped  during 
the  summer,  and  consequently  had  formed  well  developed  laterals. 
This  vine  has  been  cut  back  to  the  same  length  as  that  shown  in  Fig.  40. 
One  bud  has  been  left  of  each*  lateral  giving  thus  three  more  buds  to 
produce  grapes  and  shoots. 


Fig.  40. — Second  winter  pruning 
for  high  head. 


Fig.  41. — Second  winter  pruning 
of  very  vigorous  vine. 


In  all  cases  a  full  internode  has  been  left  above  the  top  bud.  This 
is  done  by  cutting  through  the  first  bud  above  the  highest  which  it  is 
desired  to  have  grow.  This  cut  is  made  in  such  a  way  as  to  destroy 
the  bud  but  to  leave  the  diaphragm  intact  and  part  of  the  swelling  of 
the  node.  This  upper  iuternode  is  left  partly  to  protect  the  upper 


BULLETIN  241-246  yiNE  PRUNING   IN    CALIFORNIA  77 

bud,  but  principally  to  facilitate  tying.  By  making  a  half  hitch  around 
this  internode  the  vine  is  held  very  firmly.  If  the  swelling  at  the  node 
of  the  destroyed  bud  is  not  left,  many  vines  will  be  pulled  out  of  the 
hitch  when  they  become  heavy  with  leaves  and  supple  with  the  flow  of 
sap  in  the  spring. 

In  tying  the  vines,  no  turns  or  hitches  must  be  made  around  any 
part  except  this  upper  internode.  A  hitch  below  the  top  bud  will 
result  in  a  crook-necked  vine  as  the  top  will  bend  over  in  the  summer 
under  the  weight  of  the  foliage.  A  hitch  lower  down  is  even  more 
harmful,  as  it  will  girdle  and  strangle  the  vine. 

A  second  tie  about  half  way  from  the  upper  internode  to  the  ground 
is  always  necessary  to  straighten  the  cane.  Even  if  the  cane  is  straight 
when  pruned,  a  second  tie  is  needed  to  keep  it  from  curving  under  the 
pressure  of  leaves  and  wind  in  the  spring.  For  high-headed  vines  three 
ties  are  usually  necessary  placed,  as  shown  in  Figs.  40  and  41. 

For  the  top  tie,  wire  is  particularly  suitable.  It  holds  better  than 
twine  and  does  not  wear.  Even  though  it  is  not  removed,  it  does  no 
harm,  as  the  part  around  which  it  is  wound  does  not  grow.  The  lower 
ties  should  be  of  softer  material,  as  wire  has  a  tendency  to  cut  into  the 
wood.  They  should  be  placed  so  that  the  cane  is  able  to  expand  as  it 
grows.  With  thin  and  especially  with  round  stakes  this  means  that 
the  tie  must  be  loose.  "With  large,  square  stakes  there  is  usually  suffi- 
cient room  for  expansion,  even  when  the  twine  is  tied  tight. 

However  careful  the  pruner,  many  of  the  vines  cannot  be  pruned 
quite  so  simply  as  those  described.  These  methods  therefore  must 
often  be  modified,  keeping  these  vines  in  mind  as  ideals  which  the 
imperfect  vines  are  made  to  approach  as  nearly  as  may  be. 

Some  of  the  vines  may  not  make  a  sufficient  growth  of  cane  to  be 
tied  up  in  the  way  indicated.  Such  vines  should  be  pruned  back  again 
to  two  buds  as  at  the  previous  winter  pruning,  and  special  care  taken 
during  the  following  summer  to  develop  a  good  cane.  Vines  in  which 
the  development  of  the  tying-up  cane  is  thus  delayed  a  year  will  usually 
make  a  very  vigorous  growth  the  following  summer  and  must  be 
topped.  The  result  at  the  following  winter  pruning  will  be  a  vigorous 
cane  with  laterals,  which  should  be  pruned  like  the  vine  in  Fig.  41. 
All  vines  which  have  not  made  a  growth  of  well  developed,  mature 
cane  of  the  length  desired  should  be  cut  back  to  two  buds.  This  length 
will  usually  be  at  least  twice  that  of  the  desired  height  of  trunk  because 
the  upper  part  of  the  cane  is  usually  badly  matured  and  with  imperfect 
buds.  It  is  bad  practice  to  cut  canes  to  intermediate  lengths,  as  this 
results  usually  in  crooked  trunks  and  inevitably  to  variations  in  the 
height  of  the  heads  of  different  vines. 


78 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


If  the  suckering,  disbudding,  and  thinning  of  shoots  have  been 
neglected,  there  will  be  more  than  one  cane  on  the  vine.  In  this  case 
all  but  the  strongest  and  best  placed  must  be  removed  and  this  treated 
like  the  single  cane  in  Figs.  39  and  40.  Unfortunately  the  strongest  is 


Fig.  42. — Third  spring,  ready  for 
disbudding. 


Fig.  43. — Third  spring,  cane  too 
short. 


often  not  the  best  placed.  In  fact,  if  tying  up  during  the  summer  has 
been  neglected  it  is  often  the  worst  placed.  The  more  vigorous  the 
vine  the  more  likely  is  the  position  of  the  canes  to  be  defective.  This 
is  especially  true  of  grafts  on  old  vines,  which  should  be  treated  like 
exceptionally  vigorous  vines  during  the  second  growing  season.  In 
these  cases  of  neglected  vines  the  best  canes  are  often  lying  flat  on  the 


BULLETIN  241-246  VINE  PRUNING  IN   CALIFORNIA  79 

ground.  It  will  require  all  the  ingenuity  and  skill  of  the  pruner  to 
get  them  into  a  more  or  less  erect  position,  and  at  the  best  they  will 
result  in  crooked,  misshapen  vines. 

By  removing  the  soil  from  around  the  base  of  the  vine  the  cane  can 
often  be  raised  more  easily  and  the  bend  will  then  be  at  least  partially 
in  the  underground  stem,  where  it  is  less  harmful.  In  the  worst  cases 
it  may  be  impossible  to  raise  a  cane.  It  is  then  necessary  to  cut  all 
the  canes  back  to  the  old  wood  and  to  develop  a  new  cane  the  next  year. 

Even  if  the  main  cane  has  been  tied  up,  the  removal  of  the  other 
canes,  if  they  are  numerous  and  large,  makes  many  serious  wounds  at 
the  collar  of  the  vine,  which,  in  some  cases,  weaken  the  vine  con- 
siderably. 

Third  Summer  Pruning. — During  the  third  season  average  vines, 
such  as  those  represented  in  Figs.  39  and  40,  will  produce  their  first 
considerable  crop  and  develop  the  canes  from  which  will  be  formed 
the  first  arms. 

Fig.  42  represents  such  a  vine  soon  after  the  starting  of  the  buds 
in  spring.  One  vigorous  shoot  about  three  inches  long  has  grown  from 
the  old  wood  and  five  fruit  buds  have  started  above  on  the  cane.  All 
the  buds  and  shoots  below  the  middle  of  the  cane  should  be  removed. 

This  will  leave  the  four  or  five  fruit  buds  and  will  give  the  vine 
the  opportunity  to  produce  eight  or  ten  bunches  of  grapes.  These 
buds  will  produce  also  at  least  four  or  five  shoots.  If  the  vine  is  very 
vigorous  and  the  season  favorable,  they  may  produce  eight,  ten  or 
more. 

This  figure  will  serve  to  illustrate  how  the  height  of  the  head  can 
be  modified  later.  When  the  five  shoots  grow  the  height  of  the  head 
will  be  determined  at  the  next  winter  pruning  by  which  two  of  the 
corresponding  canes  are  left  as  spurs.  If  the  highest  two  canes  are 
cut  back  to  spurs  and  all  others  removed,  the  vine  will  be  headed  as 
high  as  possible,  as  these  two  spurs  form  the  two  first  arms  which  de- 
termine the  length  of  the  trunk.  If  the  lowest  two  canes  are  chosen 
and  all  of  the  vine  above  them  removed,  the  trunk  will  be  made  as  low 
as  possible.  Intermediate  heights  can  be  obtained  by  using  some  other 
two  adjacent  canes  and  removing  the  rest.  It  is  often  advisable  to 
leave  some  extra  spurs  lower  than  it  is  desired  to  head  the  vine  and  to 
remove  these  lower  spurs  the  following  winter  after  they  have  borne 
a  crop.  For  example,  the  three  or  four  upper  canes  might  be  left,  if 
the  vine  is  vigorous  enough,  and  the  lowest  one  or  two  of  these  removed 
at  the  next  pruning.  This,  however,  is  not  often  necessary  with  prop- 
erly handled  vines  and  is  objectionable  because  it  makes  large  wounds 
in  the  trunk. 


80  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

Fig.  43  shows  a  vine  of  which  the  cane  is  too  short.  This  was  due 
to  the  accidental  breaking  off  of  the  upper  part  of  the  cane.  In  this 
case  it  is  best  to  remove  all  the  buds  and  shoots  but  the  uppermost  two. 
Otherwise  the  vine  may  head  out  too  low.  Such  a  vine  will  usually 
make  several  shoots  from  each  of  the  buds  left,  and  while  it  will  pro- 
duce few  grapes  the  current  year,  it  will  be  in  proper  shape  to  produce 
a  good  crop  the  following  year. 

During  this  spring  it  will  be  necessary  to  sucker  and  remove  low 
shoots  at  least  once  more.  This  can  be  done  when  the  vines  are  hoed. 


Tig.  44. — Vineyard  during  the  third  summer. 

If  the  vines  grow  vigorously,  the  shoots  should  be  pinched  when  they 
are  eighteen  to  twenty-four  inches  long  to  protect  them  from  the  wind. 

Fig.  44  shows  a  well  grown  vineyard  towards  the  end  of  the  third 
summer.  The  vines  shown  produced  at  the  rate  of  five  tons  per  acre, 
which  may  be  considered  about  two-thirds  of  a  full  crop  for  full  bearing 
vines  of  the  variety,  under  the  soil  and  climatic  conditions  of  the  vine- 
yard. The  crop  of  one  of  these  vines  left  on  the  vine  until  after  the 
fall  of  the  leaves  is  shown  in  Fig.  45. 

Third  Winter  Pruning. — At  the  end  of  the  third  season's  growth 
the  vine  should  have  a  straight,  well  developed  trunk  with  a  number 
of  vigorous  canes  near  the  top  from  which  to  form  the  arms. 

Fig.  46  represents  a  well  grown  vine  at  this  period.  No  shoots 
have  been  allowed  to  grow  on  the  lower  part  of  the  trunk  and  the  five 


BULLETIN  241-246  yiNE  PRUNING  IN  CALIFORNIA 


81 

1 


Fig.  45. — Crop  at  end  of  third  season. 


Fig.  46. — Three-year-old  vine  ready  for  pruning. 


82 


UNIVERSITY   OP    CALIFORNIA — EXPERIMENT    STATION 


buds  allowed  to  grow  above  have  produced  nine  vigorous  canes.  The 
pruner  should  leave  enough  spurs  to  supply  all  the  fruit  buds  that 
the  vine  can  utilize.  The  number,  size,  and  thickness  of  the  canes 
show  that  the  vine  is  very  vigorous  and  can  support  a  large  crop.  It 
will  depend  somewhat  on  the  variety  how  many  buds  should  be  left. 
For  a  variety  whose  bunches  average  one  pound,  and  which  produces 
two  bunches  to  the  shoot,  twelve  fruit  buds  should  give  about  twenty- 
four  pounds  or  about  seven  tons  per  acre,  if  the  vines  are  planted  12 
by  6  feet,  as  these  were.  The  number  of  spurs  will  depend  on  their 


Fig.  47. — Vine  of  Fig.  46  after  pruning  for  vase-formed  head. 

length.  Six  spurs  of  two  buds  each  will  give  the  required  number,  but 
as  some  of  these  canes  are  exceptionally  vigorous  they  should  be  left  a 
little  longer,  in  which  case  a  smaller  number  of  spurs  will  suffice. 

When  the  number  and  length  of  the  spurs  is  decided  on,  the  canes 
should  be  chosen  which  will  leave  these  spurs  in  the  most  suitable 
position  for  forming  arms.  This  position  will  depend  on  whether  we 
want  a  vase-form  or  fan-shaped  vine.  In  the  first  case,  we  choose  those 
which  will  distribute  the  spurs  most  evenly  and  symmetrically  on  all 
sides,  avoiding  any  which  cross  or  point  downwards. 

In  the  second  case,  we  choose  only  those  canes  which  run  in  the 
direction  of  the  trellis,  avoiding  canes  which  stick  out  between  the  rows. 
Downward  pointing  canes  may  be  used  in  this  case. 


BULLETIN  241-246  v!NE  PRUNING  IN  CALIFORNIA  83 

Fig.  47  shows  the  vine  after  pruning  for  a  vase-formed  head.  The 
primer  has  used  two  of  the  strongest  canes  to  form  two  three-bud  spurs 
and  three  of  medium  vigor  to  form  three  two-bud  spurs.  The  head 
is  of  good  shape,  though  some  of  the  spurs  are  a  little  too  low.  One, 
two,  or  three  of  these  may  be  removed  at  the  following  winter  pruning 
and  the  permanent  arms  and  head  of  the  vine  formed  from  canes 


A  B 

Fig.  48. — Three-year-old  vines:  A,  pruned  for  a  vase-formed,  and  B,  for  a 
fan-shaped  head. 

which  develop  on  the  two  highest  spurs.  If  the  vine  were  too  high, 
the  head  could  be  developed  the  next  year  from  the  three  lowest  spurs 
and  the  upper  part  removed. 

Fig.  48  shows  vines  of  the  same  age  of  practically  perfect  shape. 
Less  spurs  have  been  left  because  the  vines  were  less  vigorous.  It  is 
easier  to  properly  shape  vines  which  make  only  a  moderate  growth 
during  the  first  three  seasons.  On  the  other  hand,  very  vigorous  vines 


84 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


can  finally  be  brought  into  practically  perfect  shape  and  the  somewhat 
larger  and  more  numerous  wounds  necessary  are  more  easily  healed 
by  a  vigorous  vine. 


Fig.  49. — Four-year-old  vine  pruned  for  vase-formed  head. 

Pruning  After  the  Third  Winter. — For  the  pruner  who  under- 
stands the  pruning  of  young  vines  and  has  brought  them  to  approxi- 
mately the  form  represented  in  Figs.  47  and  48  the  subsequent  winter 
pruning  is  very  simple.  It  involves,  however,  one  new  idea — the  dis- 
tinction between  fruit  and  sterile  wood. 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


85 


Up  to  the  third  winter  pruning  this  distinction  is  not  necessary; 
first,  because  practically  all  the  wood  is  fruit  wood,  and  second,  be- 
cause the  necessity  of  forming  the  vine  controls  the  choice  of  wood. 
From  this  time  on,  however,  this  distinction  must  be  carefully  made. 
At  each  winter  pruning  a  number  of  spurs  of  fruit  wood  must  be  left 
to  produce  the  crop  to  be  expected  from  the  size  and  vigor  of  the  vine. 
Besides  these  fruit  spurs,  it  may  be  necessary  to  leave  spurs  of  sterile 


Fig.  50. — Four-year-old  vine  pruned  for  high  vase-formed  head. 

wood  to  permit  of  increasing  the  number  of  fruit  spurs  the  following 
year. 

This  will  be  made  clear  by  comparing  Figs.  48  A  and  49.  Fig. 
48  A  shows  a  vine  at  the  third  winter  pruning  with  two  fruit  spurs 
of  two  buds  each  and  one  fruit  spur  of  one  bud,  five  fruit  buds  in  all. 

If  these  five  fruit  buds  all  produce  vigorous  shoots  during  the 
following  summer,  they  will  supply  five  canes  of  fruit  wood  which  can 
be  used  to  form  five  fruit  spurs  at  the  following  winter  priming,  which 
will  be  about  the  normal  increase  necessary.  Some  of  these  fruit  buds, 
however,  may  produce  weak  shoots  or  shoots  SO  badly  placed  that  they 


86  UNIVERSITY    OF    CALJFORNIA — EXPERIMENT    STATION 

would  spoil  the  shape  of  the  head  if  used  for  spurs.  Other  shoots, 
however,  will  be  produced  from  base,  secondary,  and  adventitious  buds 
which,  while  less  fruitful,  can  be  used  to  form  spurs  for  the  starting 
of  new  arms. 


Fig.  51. — Seven-year-old  Carignane  vine  with  fully  developed  vase-formed 
head. 

Fig.  49  shows  a  vine  after  the  fourth  winter  pruning  which  had 
developed  from  a  vine  similar  to  that  shown  in  Fig.  48  A.  From  the 
three  fruit  spurs  left  the  previous  year  four  canes  have  been  chosen 
for  the  fruit  spurs  of  this  year.  The  old  spur  on  the  left  has  furnished 
two  new  spurs  and  the  two  old  spurs  at  the  right,  each  one  new  spur. 


BULLETIN  241-246 


VINE  PRUNING   IN    CALIFORNIA 


87 


The  pruner,  judging  that  the  vine  is  sufficiently  vigorous  to  stand  more 
wood,  has  formed  two  spurs  from  water  sprouts  which,  though  not 
likely  to  produce  much  fruit  the  first  season,  will  supply  fruit  wood 
for  the  following  year.  The  result  is  a  very  well  shaped  vine  with  six 
almost  perfectly  balanced  spurs.  These  spurs  will  develop  into  per- 
manent arms,  some  of  them  furnishing  finally  two  or  three. 


Fig.  52. — Nine-year-old  Carignane  vine  with  well  formed  arms. 


Fig.  50  shows  a  high-headed  vine  of  the  same  age.  It  has  five  spurs, 
of  which  four  are  fruit  spurs  and  one  a  spur  of  sterile  wood  left  to 
shape  the  vine.  The  two  more  or  less  horizontal  spurs  on  the  right 
will  bear  fruit  the  following  autumn  and  will  be  removed  entirely  at 
the  following  winter  pruning,  as  they  are  badly  placed.  The  arms  of 
the  vine  will  then  be  developed  from  the  three  upright  spurs,  which 
are  excellently  placed. 


88  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

Each  year  thereafter  the  same  process  must  be  followed.  First, 
enough  fruit  spurs,  as  well  placed  as  possible,  must  be  left  to  produce 
the  crop.  Second,  on  most  vines,  supplementary  spurs  of  sterile  wood 
must  be  left  to  supply  more  arms  where  they  are  needed,  and  finally, 
when  the  full  complement  of  arms  has  developed,  to  supply  new  arms 
to  replace  those  which  have  become  too  long  or  are  otherwise  defective. 

Fig.  51  shows  a  fully  formed  Carignane  vine  with  six  well  placed 
and  well  shaped  arms.  Such  a  vine  will  probably  not  need  a  larger 
number  of  arms,  but  care  must  be  taken  that  none  of  those  which  it  has 
become  too  long.  This  is  the  stage  at  which  provision  should  be  made 
for  replacing  arms  when  they  threaten  to  become  too  long.  The  arm 
on  the  left  will  in  two  or  three  years  extend  too  far  from  the  head  and 
will  be  in  danger  of  being  broken  off.  This  year,  therefore,  a  replacing 
spur  should  be  left  as  near  the  head  of  the  vine  as  possible.  Such  a 
spur  can  be  formed  from  the  upright  water  sprout  which  can  be  seen 
growing  out  of  the  three-year-old  wood  of  the  arm.  One  or  two  fruit 
spurs  can  be  formed  from  the  two  fruit  canes  above  this.  After  these 
fruit  spurs  have  borne  their  crop  the  arm  can  be  cut  back  to  the  re- 
placing spur,  which  by  that  time  will  have  furnished  the  necessary 
fruit  wood.  This  cutting  back  to  shorten  or  replace  the  arm  may  be 
done  at  the  following  or  some  subsequent  winter  pruning,  according 
to  the  way  in  which  the  growth  develops. 

Sometimes  it  is  difficult  to  find  water  sprouts  in  suitable  positions 
for  replacing  spurs.  This  may  be  due  to  weakness  of  the  vines,  which 
are  able  only  to  develop  shoots  on  the  fruit  spurs  and  have  no  surplus 
vigor  to  force  out  dormant  buds  on  the  older  wood.  This  difficulty 
can  be  met  by  shorter  pruning.  If  an  arm  is  too  long,  and  at  the  same 
time  weak,  it  should  be  pruned  to  very  short  spurs.  This  will  tend 
to  force  water  sprouts  to  start  from  the  older  wood  near  the  base  of 
the  arm. 

The  absence  of  water  sprouts  at  the  winter  pruning  may  also  be 
due  to  their  having  been  removed  during  the  summer.  When  water 
sprouts  are  removed  the  need  of  replacing  wood  should  always  be  kept 
in  mind  and  one  vigorous,  well  placed  water  sprout  left  near  the  base 
of  every  long  arm. 

Fig.  52  shows  an  old  Carignane  vine  in  which  this  periodical  short- 
ening and  replacing  of  the  arms  has  been  done  systematically.  The 
near  side  of  the  vine  is  nearly  bare  of  arms.  At  the  previous  winter 
pruning  a  replacing  spur  was  left  right  in  the  head  of  the  vine  on  the 
near  side.  This  produced  a  cane  which  is  utilized  this  year  as  a  fruit 
spur  and  which  will  develop  into  an  arm.  Another  similar  arm  is 
being  developed  this  year  from  a  water  sprout  growing  out  of  the  old 
wood  at  the  left. 


BULLETIN   241-246  yiNE   PRUNING   IN    CALIFORNIA  89 

Fig.  53  shows  an  old  vineyard  in  which  the  vines  have  been  kept 
in  good  form,  though  the  heads  are  a  little  too  low. 

Fan-Shaped  Vines. — With  all  headed  vines  the  treatment  up  to 
the  stage  represented  by  Figs.  39,  40,  and  41  is  the  same  except  for 
the  variations  in  the  height  of  the  head.  At  the  third  winter  pruning, 
however,  the  formation  of  the  head  commences,  and  the  pruner  de- 
termines whether  it  shall  be  vase-formed  or  fan-shaped.  The  pro- 
duction of  a  vase-formed  head  has  already  been  described. 

At  the  third  winter  pruning  the  vine  should  be  pruned  to  two 
spurs,  as  shown  in  Fig.  48  B.  More  vigorous  vines  should  not  be  given 
more  spurs,  as  in  Figs.  47  and  48  A,  but  the  spurs  should  be  made 


Fig.  53. — Vineyard  of  fifteen-year-old  Carignane  vines  with  low  medium 
trunks  and  vase-formed  heads. 

longer,  with  four,  five,  or  even  six  eyes  in  some  cases.  This  is  in  order 
to  obtain  some  fruit,  which  might  not  be  obtained  from  long  pruning 
varieties  by  leaving  many  spurs.  With  extremely  vigorous  vines  one 
fruit  cane  may  be  left  at  this  pruning.  The  wires  of  the  trellis  should 
be  put  up  this  year,  if  this  has  not  already  been  done. 

Figs.  54  and  55  illustrate  the  second  step  in  the  production  of  a 
fan-shaped  head.  This  form  of  head  is  used  only  for  trellised  vines 
and  long-pruned  varieties.  The  formation  of  the  head  and  the  man- 
agement of  the  fruit  canes  are  therefore  conveniently  discussed  to- 
gether. 

By  comparing  the  pruned  vine,  Fig.  55,  with  the  unpruned,  Fig.  54, 
the  method  of  priming  will  be  made  clear.8  The  unpruned  vine  shows 
two  arms,  the  spurs  of  the  previous  year,  from  one  of  which  have 
grown  three  vigorous  canes  and  from  the  other  two  somewhat  less 

3  By  mistake  the  photograph  from  which  Fig.  55  was  made  was  reversed,  so 
that  the  right  side  of  Fig.  54  corresponds  tQ  the  left  side  of  Fig.  55. 


90 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


vigorous.  The  pruned  vine  shows  a  complete  unit,  that  is.  a  fruit 
cane  with  its  accompanying  renewal  spur  on  the  vigorous  side  and  a 
spur  for  the  production  of  fruit  wood  for  the  following  year  on  the 
other  side.  If  the  vine  had  been  more  vigorous,  two  complete  units 
would  have  been  left  and  one  or  two  extra  spurs. 


Fig.  54. — Before  pruning. 


Fig.  55. — After  pruning. 


As  the  form  of  the  vine  is  determined  by  the  renewal  spurs,  special 
attention  should  be  paid  to  their  position.  In  this  case,  the  middle 
cane  on  one  arm  and  the  lower  cane  on  the  other  have  been  used  for 
renewal  spurs.  This  brings  them  both  to  the  same  height  above  the 
ground  and  determines  the  place  of  the  permanent  arms.  The  next 
year  each  of  these  spurs  will  furnish  a  fruit  cane  and  one  or  two  re- 
newal spurs.  The  arms  will  thus  in  two  or  three  years  be  increased 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


91 


to  four,  or,  with  very  large  vines,  to  six.  These  spurs  should  be  chosen 
as  nearly  as  possible  in  the  plane  of  the  trellis,  that  is,  they  should  not 
project  out  sideways.  Figs.  24  and  57  show  vines  of  this  kind  of  full 
size  and  in  full  bearing. 

The  fruit  canes  also  should  be  as  nearly  as  possible  in  the  direction 
of  the  trellis,  though  this  is  not  so  important,  as  they  can  be  bent  over 
to  the  wire  when  tied  up,  and  in  any  case  they  are  removed  the  next 
year. 

Fig.  56  shows  a  trellised  vineyard  of  Sultanina.  The  vines  are 
somewhat  irregular  and  proper  care  has  not  been  exercised  in  the 
choice  of  fruit  canes  and  renewal  spurs.  Water  sprouts  have  in  some 
instances  been  used  for  fruit  canes,  and  lack  of  care  in  the  selection 


Fig.  56. — Trellised  vineyard  of  Sultanina.    Pruning  defective. 

of  renewal  spurs  is  responsible  for  the  awkward,  ungainly  arms.  A 
vineyard  such  as  the  one  shown  will  not  only  not  bear  so  large  a  crop 
but  will  cost  twice  as  much  to  prune  as  one  in  which  the  vines  are  kept 
in  the  proper  shape. 

Fig.  57  shows  the  crop  on  a  trellised  Sultanina  pruned  by  the 
system  under  discussion.  It  shows  the  regular  open  distribution  of 
the  grapes,  all  at  about  the  same  distance  from  the  ground.  Such 
grapes  develop  and  ripen  equally  and  perfectly. 

Double-Headed  Vines. — :Some  growers  attempt  to  arrange  the  arms 
of  their  vines  in  two  stages,  one  above  the  other,  forming  double-headed 
or  two-crowned  vines.  The  method  is  applied  to  both  vase-formed  and 
trellised  vines.  It  is  open  to  the  same  criticisms  as  the  vertical  cordon, 
the  chief  of  which  is  that  it  cannot  be  maintained  permanently.  The 


92 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


BULLETIN  241-246 


VINE   PRUNING   IN    CALIFORNIA 


93 


lower  head  or  ring  of  arms  finally  becomes  weak  and  fails  to  produce 
wood. 

A  double  crown  can  be  maintained  in  trellised  vineyards,  and  has 
some  advantages,  the  chief  of  which  is  that  it  makes  it  easier  to  keep 
the  vine  in  the  single  plane  and  to  prevent  arms  getting  into  the  inter- 
rows.  Fig.  58  illustrates  a  method  of  starting  a  double  crown  in  a 
trellised  vineyard.  The  vine  represented  is  four  or  five  years  old. 
Finally  it  will  have  two  full  units  on  each  side.  The  double  trunk  is 


Fig.  58. — Trellised  vine  with  double  head. 

not  necessary,  and  is,  in  fact,  a  disadvantage,  as  one  trunk  has  a  ten- 
dency to  grow  at  the  expense  of  the  other. 

Vertical  and  Bo-wed  Canes. — Figs.  59  and  23  A  show  long-pruned 
vines  in  which  the  fruit  canes  have  been  tied  vertically  to  a  tall  stake. 
This  is  a  method  used  commonly  in  many  vineyards.  The  unit  of 
pruning  is  the  same  as  in  the  method  just  described,  consisting  of  a 
fruit  cane  and  a  renewal  spur.  The  framework  of  the  vine  consists 
of  a  trunk  of  medium  height,  with  a  vase-formed  head  consisting  of 
three  or  four  arms.  The  defects  of  this  system  have  been  pointed  out 
on  pages  59  and  60. 


94 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


It  is  used  with  fair  success  with  seedless  Sultanas  and  with  some 
wine  grapes  such  as  Colombar,  Semillon,  Cabernet,  and  Reisling,  in 


Fig.  59. — Vine  with  vertical  caues. 


the  hands  of  skillful  pruners.     The  results  with  Sultanina  are  very 
unsatisfactory.    Fig.  60  shows  a  vineyard  of  this  variety. 


BULLETIN  241-246  yiNE  PRUNING  IN    CALIFORNIA  95 

By  this  method,  on  most  of  the  vines,  the  fruit  canes  start  from 
high  up  near  the  middle  of  the  stake,  and  are  therefore  too  short  for 
the  best  results.  The  canes  which  start  from  low  down  are  in  most 
cases  suckers,  and  therefore  of  little  value  for  fruit  bearing. 

Fig.  23  B  shows  a  vine  with  bowed  canes.  The  method  of  pruning 
is  exactly  the  same  as  in  the  method  just  described.  The  bowing  of 
the  canes,  however,  overcomes  some  of  the  defects  of  that  method.  It 
is  used  regularly  in  many  wine-grape  vineyards  of  the  cooler  regions. 
It  is  unsuited  for  very  vigorous  vines  in  rich  soil. 

Vertical  Cordons. — In  head  pruning  the  treatment  of  young  vines 
up  to  the  second  or  third  winter  pruning  is  identical  for  all  systems. 


Fig.  60. — Vineyard  with  vertical  fruit  canes.     Pruning  defective. 

In  cordon  pruning  the  treatment  for  the  first  and  second  prunings  is 
also  the  same.  That  is,  the  vine  is  cut  back  to  two  buds  near  the  level 
of  the  ground  until  a  cane  sufficiently  long  to  serve  for  the  formation 
of  the  trunk  is  obtained. 

In  the  vertical  cordon  the  trunk  is  three  to  four  feet  long,  instead 
of  one  to  two,  as  in  head  pruning.  This  makes  it  necessary  to  have  a 
longer  and  more  vigorous  cane  to  start  with.  It  may  require  a  year 
longer  to  obtain  this.  That  is  to  say,  at  the  end  of  the  second  season's 
growth  many  vines  will  not  have  a  single  cane  sufficiently  developed 
to  give  the  necessary  three  and  one-half  feet  of  well  ripened  wood  and 
properly  developed  buds.  At  the  second  winter  pruning,  therefore,  it 
will  often  be  necessary  to  cut  the  vine  back  to  two  buds,  as  at  the  first 
winter  pruning. 

Finally  a  cane  of  the  required  length  will  be  obtained.  The  vine 
is  then  formed  as  already  described  for  the  second  winter  pruning  of 


96 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


headed  vines,  except  that  the  cane  is  left  longer.  This  cane  is  then 
tied  to  the  stake,  and  at  the  end  of  the  following  year  we  have  a  vine 
like  that  shown  in  Fig.  61. 


Fig.  61. — Vertical  cordon,  young  vine  unpruned. 

When  such  a  vine  is  pruned  spurs  are  left  at  intervals  along  the 
trunk,  as  shown  in  Fig.  62.  Each  of  these  spurs  is  a  fruit  spur  and  is 
also  the  commencement  of  an  arm.  The  future  treatment  of  these  arms 
is  the  same  as  that  of  the  arms  in  head  pruning. 

Fig.  63  shows  a  six-year-old  Emperor  vineyard  pruned  in  this  way. 
It  is  in  excellent  condition,  but  cannot  long  be  kept  so.  As  the  vines 


BULLETIN   241-246  yiNE  PRUNING   IN    CALIFORNIA  97 

grow  older  it  becomes  more  and  more  difficult  to  obtain  satisfactory 
growth  on  the  lower  spurs.  Finally,  the  whole  growth  of  the  vine  is 
concentrated  at  the  top  and  instead  of  a  cordon  we  simply  have  an 
inconveniently  high  headed  vine. 

Figs.  64  and  65  show  an  old  Emperor  vine  before  and  after  pruning. 
It  was  started  as  a  vertical  cordon,  but  has  finally  developed  into  the 


Fig.  62. — Vertical  cordon,  young  vine  pruned. 

form  described.  Such  a  vine  has  none  of  the  advantages  of  a  cordon 
and  is  inferior  to  a  headed  vine  of  moderate  height. 

Fig.  66  shows  a  double  vertical  cordon.  This  has  no  advantage 
over  the  single  cordon  and  all  its  disadvantages.  It  is,  moreover,  more 
Jroublesome  and  costly  to  prune  and  the  bunches  are  more  difficult  to 
gather  without  injury.  More  than  two  stems  are  sometimes  grown, 
which  increases  these  difficulties  and  defects. 

Horizontal  Cordons. — During  the  first  two  or  three  years  vines 
which  are  to  be  given  the  form  of  horizontal  cordons  are  treated  ex- 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


Fig.  63. — Vineyard  of  vertical  cordons. 


Figs.  64  and  65. — Ultimate  form  of  a  vertical  cordon,  pruned  and  unpruned, 
defective. 


BULLETIN  241-246  yiNE  PRUNING   IN   CALIFORNIA  99 

actly  as  for  vertical  cordons ;  that  is,  they  are  pruned  back  to  two  buds 
each  winter  and  the  growth  forced  by  disbudding  into  a  single  cane 
during  the  summer. 

As  soon  as  a  well  ripened  cane  of  the  required  length  is  obtained 
it  is  tied  to  a  wire  stretched  horizontally  along  the  row  at  from  twenty 
to  twenty-four  inches  from  the  ground. 

For  this  system  of  pruning  the  rows  should  be  twelve  to  fifteen 
feet  apart  and  the  vines  six,  seven,  or  eight  feet  apart  in  the  rows. 
As  the  cordon  or  trunk  of  each  vine  should  reach  the  next  vine  it  will 
have  to  be  six  to  eight  feet  long.  The  best  shape  is  obtained  when,  the 
trunk  is  all  formed  one  year  from  a  single  cane  (see  Fig.  67a).  It  is 
easier  and  sometimes  necessary,  however,  to  take  two  years  for  the 
formation  of  the  trunk  (see  Fig.  67&).  In  any  case,  the  cane  first  tied 
down  should  reach  at  least  half  way  to  the  next  vine.  The  following 
year  a  new  cane  from  the  end  of  this  should  be  used  to  complete  the 
full  length  of  the  trunk. 

In  attaching  the  cane  to  the  wire  it  must  be  bent  over  in  a  gentle 
curve  and  care  taken  not  to  break  or  injure  it.  The  proper  form  of 
the  bend  is  shown  in  Figs.  67  and  68  and  by  the  vine  at  the  left  side 
of  Fig.  69.  Sharp  bends  such  as  those  shown  by  the  vines  in  Fig.  70 
and  on  the  right  of  Fig.  69  should  be  avoided. 

The  cane  should  be  placed  on  top  of  the  wire,  but  should  not  be 
twisted  around  it.  The  end  should  be  tied  firmly  and  the  rest  of  the 
cane  supported  by  strings  tied  loosely  in  order  to  avoid  girdling  when 
the  cane  grows. 

In  the  following  spring  most  of  the  buds  on  a  good  cane  will  start. 
If  the  cane  is  short  jointed  some  of  the  shoots  should  be  removed  and 
only  those  shoots  allowed  to  develop  which  are  conveniently  situated 
for  permanent  arms.  If  the  vines  are  to  be  short  pruned,  the  arms 
should  be  developed  every  eight  to  twelve  inches  from  a  few  inches 
beyond  the  bend  to  the  extreme  end.  For  long  pruning  the  arms 
should  be  farther  apart,  twelve  to  twenty  inches.  Shoots  starting  from 
the  upper  side  of  the  cane  and  growing  vertically  upward  are  to  be 
preferred.  Shoots  starting  from  the  lower  side  should  be  rubbed  off 
as  soon  as  they  start.  As  the  shoots  develop  the  strongest  should  be 
pinched,  repeatedly  if  necessary.  This  will  tend  to  force  the  growth 
of  the  weaker  shoots  and  to  equalize  the  vigor  of  all. 

As  the  shoots  become  long  enough  they  should  be  tied  to  the  top 
wire.  This  will  insure  their  retaining  their  position  on  the  upper  side 
of  the  cordon.  Most  of  these  shoots  will  bear  grapes,  and  if  they  are 
not  tied  to  the  wire  the  weight  of  the  grapes  will  bend  them  towards 
the  ground  and  turn  the  cane  over.  The  result  will  be  that  the  next 


100 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


year  the  canes  will  be  all  on  the  under  side  of  the  cordon  and  the 
cordon  will  be  completely  bare  on  top. 


Fig.  66. — Vertical  cordon  with  double  trunk,  defective. 

Such  a  cordon  will  always  be  defective.  The  arms  grow  towards 
the  ground  and  bring  the  grapes  too  low  and  in  contact  with  the  soil. 
The  bare  top  of  the  cordon  will  be  exposed  to  the  sun,  which  will 
weaken  it  and  render  it  subject  to  fungous  decay.  This  is  what  has 
happened  to  the  defective  cordons  shown  in  Figs.  70  and  71. 


BULLETIN  241-246 


VINE   PRUNING    IN    CALIFORNIA 


101 


At  the  end  of  the  season  the  vines  should  have  produced  a  fair  crop 
and  there  should  be  from  five  to  ten  canes  growing  on  each  cordon  of 
full  length.  These  canes  are  then  pruned  back  to  two  or  three  buds, 
or  a  little  longer  for  long-pruned  varieties. 

There  is  still  danger  of  the  turning  over  of  the  cordon  during  the 
following  season.  This  must  be  provided  for  by  tying  some  of  the 
spurs  to  the  upper  wire.  One  at  the  end,  one  near  the  middle,  and 


Fig.  67. — Forming  the  cordon.     Second  winter  pruning. 

one  near  the  bend  are  sufficient.  In  cases  where  short  spurs  are  used 
three  of  them  must  be  left  long  enough  to  reach  the  wire  and  the  extra 
buds  cut  off  either  at  the  winter  pruning  or  when  they  start  in  the 
spring.  In  subsequent  years  the  cordon  will  be  heavy  and  rigid  enough 
to  be  safe  from  turning  over. 


Fig.  68. — Completed  cordon  (unilateral).     Half -long  pruning. 

During  the  following  spring  and  summer  the  vines  should  be  care- 
fully suckered  and  unnecessary  water  sprouts  removed.  Any  shoots 
coming  from  the  lower  side  of  the  cordon  should  be  removed  early  to 
strengthen  the  growth  in  the  shoots  on  the  upper  side.  Neglect  of  this 
precaution  is  shown  by  the  vines  in  Figs.  70  and  71.  Such  vines  are 
apt  to  become  dry  or  decayed  on  the  upper  side.  At  the  end  of  this 
year,  which  should  be  the  fourth  or  fifth  from  planting  at  the  latest, 
the  cordon  will  be  fully  formed  and  the  final  style  of  pruning  can  be 
applied.  A  short-pruned  cordon  vine  is  shown  in  Fig.  26.  The  arms 
and  spurs  are  a  little  too  numerous  and  too  close  together.  If  this 


102 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


vine  required  the  number  of  buds  shown  it  would  have  been  better  to 
have  left  the  fruit  spurs  longer  and  to  have  left  fewer  and  shorter  wood 
spurs. 

Fig.  68  shows  a  cordon  pruned  half  long.  This  is  an  excellent 
system  for  Malaga,  Emperor,  and  Cornichon  when  growing  in  very 
fertile  soil.  It  gives  the  half-long  fruit  canes  which  these  varieties 
need  to  produce  good  crops. 

Fig.  69  shows  a  well  formed  cordon  in  full  bearing.    The  vine  is 


Fig.  69. — Unilateral  horizontal  cordon;  var.  Semillon. 

Semillon  grafted  on  St.  George  and  is  pruned  short.  The  Semillon  is 
a  variety  which  usually  requires  long  pruning,  but  the  combined  effects 
of  grafting  on  resistant  stock  and  horizontal  cordon  pruning  have  in- 
creased its  fertility  so  that  a  sufficient  crop  is  obtained  from  short 
spurs.  If  such  a  vine  were  pruned  long  it  would  quickly  exhaust  itself, 
except  in  the  richest  soil. 

Fig.  70  shows  an  old  Semillon  cordon  with  several  defects.  The 
bend  is  too  short  and  the  growth  of  cane  is  all  from  the  lower  side. 
The  half-long  canes  in  this  case  will  not  exhaust  the  vine  because  most 
of  them  are  water  sprout  canes  and  will  bear  little. 

Fig.  71  gives  a  view  of  the  vineyard  in  which  the  vine  of  Fig.  70 
grew.  Little  or  no  benefit  is  obtained  from  cordons  handled  in  this 
way. 


BULLETIN  241-246  VINE  PRUNING  IN  CALIFORNIA  103 

Fig.  72  shows  a  vineyard  of  Colombar,  illustrating  a  bilateral  cordon. 
With  vines  at  the  same  distance  apart,  each  cordon  is  only  half  the 
length  of  a  unilateral  cordon.  It  is  a  little  easier  to  establish  but  more 
difficult  to  keep  in  good  form.  One  branch  tends  to  become  stronger 
than  the  other  and  in  windy  situations  the  branch  growing  toward  the 
prevailing  wind  is  more  subject  to  injury. 

Renovation  of  Imperfect  or  Misshapen  Vines. — The  pruner  with 
definite  ideas  who  properly  handles  his  vines  from  the  beginning  can, 
in  most  cases,  bring  them  into  the  required  shape  with  comparative 


Fig.  70. — Defective  cordon. 

ease.  Often,  perhaps  usually,  he  has  to  deal  with  vines  which  have 
some  more  or  less  serious  fault.  They  may  be  misshapen  owing  to 
defective  pruning,  or  otherwise-  imperfect,  owing  to  mechanical  in- 
juries, or  as  the  result  of  frost,  fungi,  or  insect  pests. 

If  the  vines  are  young,  the  defects  can  often  be  overcome  and  the 
vine  given  a  proper  form  very  easily. 

Fig.  73  shows  a  vine  at  the  end  of  the  year  after  tying  up.  Most 
of  the  growth  has  gone  into  a  cane  near  the  base  and  the  growth  from 
the  top  buds  has  been  poor.  This  condition  is  likely  to  occur  when  a 
small  or  imperfectly  ripened  cane  has  been  used  from  which  to  at- 
tempt to  form  a  trunk.  There  are  three  possible  ways  of  pruning  this 
vine.  First,  the  two  small  canes  at  the  top  may  be  cut  back  to  form 
spurs  and  all  other  canes  removed.  This  will  give  a  vine  with  the  head 
at  the  right  height,  but  all  the  best  wood  has  been  cut  off.  It  will 
result  in  four  large  wounds  on  the  trunk,  and  the  vine  will  require  a 


104 


UNIVERSITY    OP    CALIFORNIA EXPERIMENT    STATION 


great  deal  of  attention  during  the  following  growing  season,  as  water 
sprouts  will  be  numerous  and  vigorous  on  the  lower  and  healthier 
portion  of  the  vine.  Moreover,  the  attempt  to  force  the  growth  into 
the  weak  top  will  delay  the  development  of  the  vine  and  even  result 
in  a  permanently  weak  top. 

Second,  two  or  three  of  the  canes  about  the  middle  of  the  trunk 
may  be  cut  back  to  spurs  and  the  rest  removed,  including  the  whole 


-Detective 


top  and  the  largest  cane  at  the  bottom.  This  will  give  a  healthier  and 
stronger  vine,  but  the  head  will  be  too  low. 

Third,  a  new  trunk  may  be  started  from  the  strong  cane  near  the 
bottom  and  the  whole  growth  above  removed,  as  shown  in  Fig.  74. 
This  preserves  the  strongest  cane,  on  which  most  of  the  energies  of  the 
vine  were  expended  during  the  preceding  season,  only  one  large  wound 
is  made,  and  all  the  defective  and  dwarfed  parts  of  the  vine  are  re- 
moved. The  formation  of  the  head  is  deferred  one  year,  but  the  vine 
will  have  a  stronger,  healthier,  and  better  formed  trunk,  and  will 
probably  bear  as  much  the  following  year  as  if  pruned  in  either  of  the 
other  ways. 

In  any  vineyard  many  of  the  vines,  in  some,  most  of  them,  will  show 
imperfections  or  abnormalities  of  a  similar  nature.  No  general  rule 
of  treatment  can  be  given;  each  vine  is  a  separate  problem.  The 


BULLETIN  241-246  yiNE  PRUNING   IN   CALIFORNIA  105 

primer  should  endeavor  to  choose  that  method  in  each  case  which  will 
finally  and  most  quickly  give  him  a  vine  of  the  desired  form  while 
utilizing  as  much  as  practicable  the  best  and  most  vigorous  parts  of  the 
vine  and  making  as  few  and  as  small  wounds  as  possible. 

As  the  vines  become  older  it  becomes  increasingly  difficult  to  over- 
come defects  of  formation.  The  disadvantage  of  a  low  head  may  be 
in  part  avoided  by  gradually  lengthening  the  arms  and  giving  them  a 
more  vertical  direction.  An  ill-formed  head  may  be  improved  by  re- 
moving badly  placed  arms  and  developing  new  arms  where  needed. 

The  trunks  of  many  old  vines  are  so  defective  that  little  improve- 


Fig.  72. — Vineyard  of  horizontal  cordons,  bilateral. 

ment  can  be  obtained  by  these  means.  It  is  possible  and  occasionally 
profitably  to  completely  renew  the.  trunks  of  such  vines.  This  can  be 
done  by  developing  a  new  trunk  from  a  strong  cane  originating  at  or 
below  the  surface  of  the  ground  and  then  cutting  away  the  old  trunk. 
This  method  has  the  same  defect  as  the  grafting  of  old  vines.  It 
leaves  a  large  wound  where  the  old  stump  was  removed,  a  wound  which 
can  never  heal  and  which  finally  allows  the  entrance  of  wood-rot  fungi. 
Such  renewed  vines,  however,  'may  last  as  long  as  if  the  old  decayed 
trunk  had  been  left  or  longer.  They  will  also  be  more  fruitful  and 
easier  to  handle  properly.  The  change  can  be  made  without  the  loss 
of  a  crop  that  occurs  in  grafting.  If  the  stumps  are  large,  the  expense 
of  sawing  them  off  is  considerable. 


106 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


Choice  of  a  System. — In  choosing  a  system  we  must  consider  care- 
fully the  characteristics  of  the  particular  variety  we  are  growing.  A 
variety  which  bears  only  on  the1  upper  buds  must  be  pruned  "long," 
that  is,  must  be  given  fruit  canes.  It  should  be  noted  that  many 
varieties,  such  as  Petite  Sirah,  which  will  bear  with  short  pruning  when 
grafted  on  resistant  roots,  require  fruit  canes  when  growing  on  their 
own  roots.  In  general,  grafted  vines  require  shorter  pruning  than 


Fig.  73. — Young  vine  with  imperfect  top. 

ungrafted.  If  pruned  the  same,  the  grafted  vines  may  overbear  and 
quickly  exhaust  themselves.  This  seems  to  be  the  principal  reason  for 
the  frequent  failure  of  Muscat  vines  grafted  on  resistant  stock.  The 
cultural  conditions  also  affect  the  vine  in  this  respect.  Vines  made 
vigorous  by  rich  soil,  abundant  moisture,  and  thorough  cultivation 
require  longer  pruning  than  weaker  vines  of  the  same  variety. 

The  normal  size  of  the  bunch  is  als.o  of  importance.  This  size  will 
vary  from  one-quarter  of  a  pound  to  two  or  three  pounds.  It  is  diffi- 
cult to  obtain  a  full  crop  from  a  variety  whose  bunches  are  very  small, 
without  the  use  of  fruit  canes.  Spurs  will  not  furnish  enough  fruit 
buds  without  crowding  them  inconveniently.  On  the  other  hand,  some 
shipping  grapes  may  bear  larger  crops  when  pruned  long,  but  the 
bunches  and  berries  may  be  too  small  for  the  best  quality. 


BULLETIN  241-246 


VINE   PRUNING    IN    CALIFORNIA 


107 


The  possibilities  of  development  vary  much  with  different  varieties. 
A  Mission  or  Flame  Tokay  may  be  made  to  cover  a  quarter  of  an  acre 
and  develop  a  trunk  four  or  five  feet  in  circumference.  A  Zinfandel 
vine  under  the  same  conditions  would  not  reach  a  tenth  of  this  size  in 
the  same  time.  Vines  in  a  rich  valley  soil  will  grow  much  larger  than 
on  a  poor  hillside.  The  size  and  shape  of  the  trunk  must  be  modified 
accordingly  and  adapted  to  the  available  room  or  number  of  vines  to 
the  acre. 


Fig.  74. — Pruning  to  renew  imperfect  top  of  vine  of  Fig.  73. 

The  shape  of  the  vine  must  be  such  as  to  protect  it  as  much  as 
possible  from  various  unfavorable  conditions.  A  variety  susceptible 
to  oidium,  like  the  Carignane,  must  be  pruned  so  that  the  fruit  and 
foliage  are  not  unduly  massed  together.  Free  exposure  to  light  and 
air  are  a  great  protection  in  this  respect.  The  same  is  true  for  varieties 
like  the  Muscat,  which  have  a  tendency  to  "coulure"  if  the  blossoms 
are  too  moist  or  shaded.  In  frosty  locations  a  high  trunk  will  be  a 
protection,  as  the  air  is  always  colder  close  to  the  ground. 

The  qualities  required  in  the  crop  also  influence  our  choice  of  a 
pruning  system.  With  wine  grapes,  even,  perfect  ripening  and  full 
flavor  are  desirable.  These  are  obtained  best  by  having  the  grapes  at 
a  uniform  height  from  the  ground  and  as  near  to  it  as  possible.  The 


108  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

same  qualities  are  desirable  in  raisin  grapes,  with  the  addition  of  large 
size  of  the  berries.  With  shipping  grapes  the  size  and  perfection  of 
the  berries  and  bunches  are  the  most  essential  characteristics.  The 
vine,  therefore,  should  be  so  formed  that  each  bunch  hangs  clear,  free 
from  injurious  contact  with  canes  or  soil  and  equally  exposed  to  light 
and  air. 

The  maximum  returns  in  crop  depend  on  the  early  bearing  of 
young  vines,  the  regularity  of  bearing  of  mature  vines,  and  the  long- 
evity of  the  vineyard.  These  are  insured  by  careful  attention  to  all 
the  details  of  pruning,  but  are  possible  only  when  the  vines  are  given  a 
suitable  form. 

The  running  expenses  of  a  vineyard  depend  in  a  great  measure  on 
the  style  of  pruning  adopted.  Vines  of  suitable  form  are  cultivated, 
pruned,  and  the  crop  gathered  easily  and  cheaply.  This  depends  also 
both  on  the  form  of  vine  adopted  and  on  care  in  details. 

It  is  impossible,  therefore,  to  state  for  any  particular  variety  or 
any  particular  location  the  best  style  of  pruning  to  be  adopted.  All 
that  can  be  done  is  to  give  the  general  characteristics  of  the  variety 
and  to  indicate  how  these  may  be  modified  by  grafting,  soil,  or  climatic 
or  other  conditions. 

The  most  important  characteristic  of  the  variety  in  making  a  choice 
of  a  pruning  system  is  whether  it  normally  or  usually  requires  long 
or  half-long  pruning.  With  this  idea,  the  principal  grapes  grown 
in  California,  together  with  all  those  grown  at  the  Experiment  Station 
on  which  data  exist,  have  been  divided  into  five  groups  in  the  following 
list: 

1.  Varieties  Which  Require  Long  Pruning  Under  All  Conditions. — 
Clairette  blanche,  Corinth  white  and  black,  Seedless  Sultana,  Sultanina 
white  (Thompson's  Seedless)  and  rose. 

2.  Varieties   Which    Usually   Require  Long  Pruning. — Bastardo, 
Boal   de   Madeira,    Chardonay,    Chauche   gris   and   noir,   Colombar, 
Crabbe's  Black  Burgundy,  Dizmar,  Gamais,  Kleinberger,  Luglienga, 
Marsanne,  Marzemino,  Merlot,  Meunier,  Muscadelle  de  Bordelais,  Neb- 
biolo,  Pagadebito,  Peverella,  Pinots,  Rieslings,  Rish  Baba,  Robin  noir, 
Rulander,  Sauvignon  blanc,  Semillon,  Serine,  Petite  Sirah,  Slanca- 
menca,  Steinschiller,  Tinta  Cao,  Tinta  Madeira,  Trousseau,  Verdelho, 
Petit  Verdot,  Walchriesling. 

3.  Varieties   Which    Usually   Require   Short   Pruning. — Aleatico, 
Aligote,  Aspiran,  Bakator,  Bouschets,  Blaue  Elbe,  Beba,  Bonarda, 
Barbarossa,  Catarattu,  Charbono,  Chasselas,  Durif,  Freisa,  Frontig- 
nan,  Furmint,  Grand  noir,  Grosseblaue,  Green  Hungarian,  Malmsey, 


BULLETIN   241-246  VINE   PRUNING    IN    CALIFORNIA  109 

Mantuo,  Monica,  Mission,  Moscatello  fino,  Mourisco  branco,  Mourisco 
preto,  Negro  amaro,  Palomino,  Pedro  Zumbon,  Perruno,  Pizzutello  di 
Roma,  Black  Prince,  West's  White  Prolific,  Quagliano,  Rodites,  Rozaki, 
Tinta  Amarella,  Vernaccia  bianca,  Vernaccia  Sarda. 

4.  Varieties  Which  Require  Short  Pruning  Under  All  Conditions. — 
Aramon,  Burger,  Black  Morocco,  Mourastel,  Muscat  of   Alexander, 
Napoleon,  Picpoule  blanc  and  noir,  Flame  Tokay,  Ugni  blanc,  Verdal, 
Zinfandel. 

5.  Varieties  of  Table  Grapes  Which  Usually  Require  Half-Long  or 
Cordon  Pruning. — Almeria  (Ohanez),  Bellino,  Bermestia  bianca  and 
violacea,  Cipro  nero,  Dattier  de  Beirut,  Cornichon,  Emperor,  Black 
Ferrara,  Malaga,  Olivette  de  Cadenet,  Pis-de-Chevre  blanc,  Schirad- 
zouli,  Zabalkanski. 

These  lists  must  not  be  taken  as  indicating  absolutely  for  all  cases 
how  these  varieties  are  to  be  pruned.  They  simply  indicate  their 
natural  tendencies.  Certain  methods  and  conditions  tend  to  make 
vines  more  fruitful.  Where  these  occur  shorter  pruning  than  is  indi- 
cated may  be  advisable.  On  the  other  hand,  other  methods  and  con- 
ditions tend  to  make  the  vines  vigorous  at  the  expense  of  fruitfulness. 
Where  these  occur  longer  pruning  may  be  advisable. 

The  more  usual  factors  which  tend  toward  fruitfulness  are : 

Grafting  on  resistant  vines,  especially  on  certain  varieties  such  as 
those  of  Riparia  and  Berlandieri ; 

Old  age  of  the  vines ; 

Mechanical  or  other  injuries  to  any  part  of  the  vine ; 

Large  development  of  the  trunk,  as  in  the  cordon  systems. 

The  more  usual  factors  which  tend  toward  vigor  at  the  expense  of 
fruitfulness  are : 

Rich  soil,  especially  large  amounts  of  humus  and  nitrogen ; 

Youth  of  the  vines ; 

Excessive  irrigation  or  rainfall  (within  limits). 

In  deciding  what  system  of  pruning  to  adopt,  all  these  factors, 
together  with  the  nature  of  the  vine  and  the  uses  to  which  the  fruit  is 
to  be  put,  must  be  considered.  It  is  best  when  the  vineyard  is  started 
to  err  on  the  side  of  short  pruning.  While  this  may  diminish  slightly 
the  first  one  or  two  crops,  the  vines  will  gain  in  vigor  and  the  loss  will 
be  made  up  in  subsequent  crops.  If  the  style  of  pruning  adopted 
results  in  excessive  vigor  of  the  vines,  it  should  be  gradually  changed 
in  the  direction  of  longer  pruning  with  the  object  of  utilizing  this 
vigor  in  the  production  of  crop. 


110  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

This  change  should  be  gradual,  or  the  risk  is  run  of  injuring  the 
vitality  of  the  vines  by  one  or  two  excessively  heavy  crops.  Finally, 
each  year  the  condition  of  the  individual  vine  should  determine  the 
kind  of  pruning  to  be  adopted.  If  the  vine  appears  weak,  from  what- 
ever cause,  it  should  be  pruned  shorter  or  given  less  spurs  or  fruit 
canes  than  the  year  before.  On  the  contrary,  if  it  appears  unneces- 
sarily vigorous,  more  or  longer  spurs  or  fruit  canes  should  be  left. 
Every  vine  should  be  judged  by  itself.  It  is  not  possible  to  give  more 
than  general  directions  for  the  pruning  of  the  whole  vineyard.  It 
cannot  be  well  pruned  unless  the  men  who  do  the  actual  pruning 
understand  their  work  and  are  capable  of  using  sufficient  judgment  to 
properly  modify  their  methods  for  each  individual  vine. 


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No. 
185. 

251. 

253. 

261. 
262. 

263. 
266. 

267. 
268. 
270. 


271. 
272. 
273. 

274. 
275. 

276. 
278. 
279. 
280. 

282. 

283. 
285. 
286. 
288. 


No. 

70. 

76. 
82. 

113. 
114. 
115. 
126. 
127. 
128. 
129. 
130. 
131. 
135. 
137. 
138. 
139. 

143. 

144. 
148. 
152. 

153. 
154. 

155. 
156. 
157. 
158. 
159. 
160. 
164. 


BULLETINS 

No. 

Report  of  Progress  in  Cereal  Investiga-  290. 

tions. 

Utilization  of  the  Nitrogen  and  Organic  299. 

Matter   in    Septic    and    Imhoff    Tank  300. 

Sludges.  301. 
Irrigation    and    Soil    Conditions    in    the 

Sierra  Nevada  Foothills,  California.  302. 
Melaxuma  of  the  Walnut,  "  Juglans  regia." 

Citrus    Diseases    of    Florida    and    Cuba  303. 

Compared  with  Those  of  California.  304. 
Size  Grades  for  Ripe  Olives. 

A  Spotting  of  Citrus  Fruits  Due  to  the  308. 

Action  of  Oil  Liberated  from  the  Rind. 
Experiments  with  Stocks  for  Citrus. 
Growing  and  Grafting  Olive  Seedlings.  _  309. 
A  Comparison  of  Annual  Cropping,  Bi- 
ennial Cropping,  and  Green  Manures  310. 

on  the  Yield  of  Wheat.  311. 

Feeding  Dairy  Calves  in  California.  312. 

Commercial  Fertilizers.  313. 

Preliminary    Report    on    Kearney    Vine-  316. 

yard  Experimental  Drain.  317. 

The  Common  Honey  Bee  as  an  Agent  in  318. 

Prune  Pollination.  319. 

The  Cultivation  of  Belladonna  in  Cali-  320. 

fornia.  321. 

The  Pomegranate.  322. 

Grain  Sorghums.  323. 
Irrigation  of  Rice  in  California. 

Irrigation  of  Alfalfa  in  the  Sacramento  324. 

Valley. 

Trials  with   California  Silage  Crops  for  325. 

Dairy  Cows. 

The  Olive  Insects  of  California. 

The  Milch  Goat  in  California.  326. 

Commercial  Fertilizers.  327. 
Potash    from    Tule    and    the    Fertilizer 

Value  of  Certain  Marsh  Plants. 


Observations    on    the    Status    of    Corn 

Growing  in  California. 
Hot  Room  Callusing. 
The     Common     Ground     Squirrels     of 

California. 

Correspondence  Course*  m  Agriculture. 
Increasing  the  Duty  oi  Water. 
Grafting  Vinifera  Vineyards. 
Spraying  for  the  Grape  Leaf  Hopper. 
House  Fumigation- 
Insecticide  Fo-mulas. 
The  Control  of  Citrus  Insects. 
Cabbage  Growing  in  California. 
Spraying  /or  Control  of  Walnut  Aphis. 
Official  Tests  of  Dairy  Cows. 
Wood  Decay  in  Orchard  Trees. 
The  Silo  in  California  Agriculture. 
The  Generation  of  Hydrocyanic  Acid  Gas 

\n  Fumigation  by  Portable  Machines. 
Control    of    Grasshoppers    in     Imperial 

Valley. 

Oidium  or  Powdery  Mildew  of  the  Vine. 
"Lungworms". 
Some  Observations  on  the  Bulk  Handling 

of  Grain  in  California. 
Announcement    of   the    California    State 

Dairy  Cow  Competition,  1916-18. 
Irrigation    Practice    in    Growing    Small 

Fruits  in  California. 
Bovine  Tuberculosis. 
How  to  Operate  an  Incubator. 
Control  of  the  Pear  Scab. 
Home  and  Farm  Canning. 
Agriculture  in  the  Imperial  Valley. 
Lettuce  Growing  in  California. 
Small  Fruit  Culture  in  California. 


CIRCULARS 

No. 
165. 


167. 
168. 

169. 
170. 

172. 
173. 
174. 
175. 

176. 

177. 
178.. 
179. 

181. 
182. 

183. 
184. 
185. 

188. 
189. 
190. 
191. 
193. 
198. 
201. 
202. 


The  June  Drop  of  Washington  Navel 
Oranges. 

The  Use  of  Lumber  on  California  Farms. 

Commercial  Fertilizers. 

California  State  Dairy  Cow  Competition, 
1916-18. 

Control  of  Ground  Squirrels  by  the 
Fumigation  Method. 

Grape  Syrup. 

A  Study  on  the  Effects  of  Freezes  on 
Citrus  in  California. 

I.  Fumigation  with  Liquid  Hydrocyanic 
Acid.  II.  Physical  and  Chemical  Pro- 
perties of  Liquid  Hydrocyanic  Acid. 

I.  The  Carob  in  California.  II.  Nutri- 
tive Value  of  the  Carob  Bean. 

Plum  Pollination. 

Investigations  with  Milking  Machines. 

Mariout  Barley. 

Pruning  Young  Deciduous  Fruit  Trees. 

The  Kaki  or  Oriental  Persimmon. 

Selections  of  Stocks  in  Citrus  Propagation. 

The  Effects  of  Alkali  on  Citrus  Trees. 

Caprifigs  and  Caprification. 

Control  of  the  Coyote  in  California. 

Commercial  Production  of  Grape  Syrup. 

The  Evaporation  of  Grapes. 

Heavy  vs.  Light  Grain  Feeding  for  Dairy 
Cows. 

Storage  of  Perishable  Fruit  at  Freezing 
Temperatures. 

Rice  Irrigation  Measurements  and  Ex- 
periments in  Sacramento  Valley,  1914- 
1919. 

Brown  Rot  of  Apricots. 

Commercial  Fertilizers. 


Fundamentals    of    Sugar    Beet    Culture 

under  California  Conditions. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morning- 
Glory  within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing  California  Soils  for  the   1918 

Crop. 

Wheat  Culture. 

The  Construction  of  the  Wood-Hoop  Silo. 
Farm  Drainage  Methods. 
Progress  Report  on  the  Marketing  and 

Distribution  of  Milk. 
Hog  Cholera  Prevention  and  the  Serum 

Treatment. 
Grain  Sorghums. 

The  Packing  of  Apples  in  California. 
Factors  of  Importance  in  Producing  Milk 

of  Low  Bacterial  Count. 
Control  of  the  California  Ground  Squirrel. 
Extending  the  Area  of  Irrigated  Wheat  in 

California  for  1918. 
Infectious  Abortion  in  Cows. 
A  Flock  of  Sheep  on  the  Farm. 
Beekeeping  for  the  Fruit-grower  and  Small 

Rancher  or  Amateur. 
Lambing  Sheds. 
Winter  Forage  Crops. 
Agriculture  Clubs  in  California. 
Pruning  the  Seedless  Grapes. 
A  Study  of  Farm  Labor  in  California. 
Syrup  from  Sweet  Sorghum. 
Helpful  Hints  to  H9g  Raisers. 
County  .Organization    for     Rural     Fire 

Control. 


CIRCULARS — Continued 


No. 

203.  Peat  aa  a  Manure  Substitute. 

205.  Blackleg. 

206.  Jack  Cheese. 

207.  Neufchatel  Cheese. 

208.  Summary  of  the  Annual  Reports  of  the 

Farm  Advisors  of  California. 
210.  Suggestions  to  the  Settler  in  California. 

214.  Seed    Treatment   for   the   Prevention   of 

Cereal  Smuts. 

215.  Feeding  Dairy  Cows  in  California. 

217.  Methods    for    Marketing    Vegetables    in 

California. 

218.  Advanced  Registry  Testing  of  Dairy  Cows. 


No. 

219.  The  Present  Status  of  Alkali. 

220.  Unfermentcd  Fruit  Juices. 

221.  How  California  is  Helping    People  Own 

Farms  and  Rural  Homes. 

222.  Fundamental  Principles  of  Co-operation 

in  Agriculture. 

223.  The  Pear  Thrips. 

224.  Control  of  the  Brown  Apricot  Scale  and 

the  Italian  Pear  Scale  on  Deciduous 
Fruit  Trees. 

225.  Propagation  of  Vines. 

226.  Protection    of    Vineyards    from    Phyl- 

loxera. 


